Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

How many different ways can four team members from the group of fifteen be lined up for a photograph?

Answer»

To form a TEAM of 4 from the 15 people:

Number of choices for the first PERSON = 15 (That is, any of the 15 people)

Number of choices for the second person = 14 (That is, any of the 14, excluding the one chosen earlier)

Number of choices for the third person = 13 (That is, any of the 13, excluding the ONES chosen earlier)

Number of choices for the fourth person = 12 (That is, any of the 12, excluding the ones chosen earlier)


Find the number of possible combinations:

Number of possible combinations = 15 x 14 x 13 x 12 = 32760


Answer: 32760 different combinations

2.

the sum of present ages of Anil and his father is 54 years six years ago Anil father was 6 times as old as Anil find their present ages

Answer» THANKS for your QUESTION.
3.

using Pythagoras Theorem find the hypotenuse of right angle triangle whose side is 40 cm and 9cm how to solve this question

Answer»

Heya!!

Here is your answer.

We KNOW that the hypotenuse is the LARGEST side in a right-angled triangle.

And, the formula of Pythagoras theorem is
a²+b² = c²

Where, a = base/PERPENDICULAR, b=base/perpendicular and c=hypotenuse

a and b are the two sides of the triangle i.e the legs.(the base and perpendicular of a triangle are together CALLED the legs)

Now, let's solve the problem USING Pythagoras theorem.

a²+b² = c²

=>c² = 40²+9²

=>c² = 1600+81

=> c² = 1681

=> c = √1681

=> c = 41

⭐ Hope it helps you ⭐

4.

The area of a right angle triangle is 30cm square its hypotenuse is 13cm.find the length of the smaller side

Answer» HEY dear your ANSWER is here
any CONFUSION ASK in COMMENT....
5.

Write equations for the following statement.( a) The sum of number x and 4 is 9 (b)ten times a is 70

Answer»

A)x+4=9
b)10a=70...................

6.

Factorize 81a^4-16b^4

Answer» HOPE it helps...PLEASE mark my answer as BRAINLIEST.
7.

Factorise 4X square + 9 y square + 16 z square + 12 x y - 24 yz-16xz

Answer»

4x²+9y²+16z²+12xy-24yz-16xz

= (2X)²+(3Y)²+(-4Z)²+2[(2x)(3y)+(3y)(-4z)+(-4z)(2x)]

=(2x+3y-4z)²

8.

half the perimeter of a rectangular Garden whose length is 4m more than its width is 36 M find the dimensions of the garden

Answer» HOPE it HELPS MARK as BRAINLIEST
9.

A farmer has a field in the form of a parallelogram PQRS as shown in the figure. He took the mid- point A on RS and joined it to points P and Q. In how many parts of field is divided? What are the shapes of these parts?The farmer wants to sow groundnuts which are equal to the sum of pulses and paddy. How should he sow? State reasons?

Answer»

If a parallelogram and a triangle are on the same base and between the same parallels then area of the triangle is half the area of the parallelogram.


solution :

Given: PQRS is a parallelogram and A is any point RS.


Now join AP and AQ. Thus, the field will be divided in 3 parts and each part is in the shape of triangle.


Since , ∆APQ & parallelogram PQRS lie on the same base PQ and between same Parallel Lines PQ & SR.


AR(∆APQ)= ½ ar(||gm PQRS)........(i)


Then, remaining


ar(∆ASP)+ ar(∆ARQ)= ½ ar(||gm PQRS)........(ii)


From eq (i) & (ii)


ar(∆APQ)= ar(∆ASP)+ar(∆ARQ)


So FARMER has two OPTIONS:

Either the farmer can sow wheat in ∆APQ and pulses in other two TRIANGLES or pulses in ∆APQ  and wheat in other two triangles.


Hope this will help you...

10.

The bisectors of the angle of a parallelogram enclose a-A) ParallelogramB) RhombusC) RectangleD) Square

Answer» RECTANGLE............
Given: ABCD is a parallelogram. AE bisects ∠BAD. BF bisects ∠ABC. CG bisects ∠BCD and DH bisects ∠ADC
To prove: LKJI is a rectangle
∠BAD + ∠ABC = 180° because adjacent ANGLES of a parallelogram are supplementary
 
 
[Since SUM of adjacent angles of a parallelogram are supplementary]
 
ΔABJ is a RIGHT triangle since its acute interior angles are complementary
Similar in ΔCDL we get ∠DLC = 90° and in ΔADI we get ∠AID = 90°
Then ∠JIL = 90° as ∠AID and ∠JIL are vertical opposite angles
Since three angles of quadrilateral LKJI are right angles, hence 4th angle is also a right angle.
Thus LKJI is a rectangle.
11.

a rational number is such that when you multiply it by 5/2 and add 2/3 to the product you get -7/2. what is the number

Answer» HEY MATE!! that's your answer-

let x be the rational NUMBER

according to QUESTION,

x* 5/2 + 2/3 = -7/2

x * (15 + 4)/6 = -7/2. ( by taking LCM of 2 & 3 we get 6 as denominator)

x* 19 /6 = -7/2

x \: = \frac{ - 7}{2} \times \frac{6}{19}

x = \frac{ - 21}{19}

so rational number = -21/19

hope it was helpful!!✌️
if you like plz mark as brainliest!!
12.

Find the sum of 1.2.3+2.3.4+3.4.5+ ……….up to n terms ?

Answer»

Here, A n for the equation is n(n+1)(n+2)

=(n^2+n)(n+2)

=n^3+3n^2+2n

Therefore, A 1 = 1^3+(3*1^2)+(2*1)

A 2 =2^3+(3*2^2)+(2*2)…

A n =n^3+(3*n^2)+(2*n)

So,

S n

=(1^3+2^3+3^3…+n^3)

+3(1^2+2^2+3^2…+n^2)+2(1+2+3+…+n)

={「n(n+1)」/2}^2

+3{「n(n+1)(2n+1)」/6}+2{「n(n+1)/2}

=[n(n+1)]/2{[n(n+1)]/2 + [3(2n+1)]/3+2}

=[n(n+1)]/2{[n^2+n+4n+2+4]/2}

=[n(n+1)]/4{n^2+5n+6}

=[n(n+1)]/4{n^2+3n+2n+6}

=[n(n+1)(n+2)(n+3)]/4

13.

Find the square root of 53361 by division method

Answer»

\textbf{Given:}

\text{Number is}\;53361

\textbf{To find:}

\text{The square root of $53361$}

\textbf{Solution:}

\text{We apply long division <klux>METHOD</klux> to find the square root of 53361}

\begin{array}{r|lllll}&2&3&1&&\\\cline{2-6}&&&&&\\2&5&3&3&6&1\\&&&&&\\&4&&&&\\\cline{2-6}&&&&&\\43&1&3&3&&\\&&&&&\\&1&2&9&&\\\cline{2-6}&&&&&\\461&&&4&6&1\\&&&&&\\&&&4&6&1\\&&&&&\\\cline{2-6}&&&&&\\&&&&&0\\&&&&&\\\cline{2-6}\end{array}

\bf\therefore\sqrt{53361}=231

Find more:

1.Find the square root by long division method.

(i)17956 (ii) 11025 (iii) 6889 (iv) 1764

(v) 418609​

brainly.in/question/14520335

2.Square root of 1849 by using division method

brainly.in/question/1656193

14.

In the adjacent figure AB||CD,EF/CD and ∠GED=126°, find ∠AGE, ∠GEF and ∠FGE.

Answer»

Alternate angles:When two lines are crossed by another line the pair of angles on opposite SIDES of the transversal is called alternate angles. 


Theorem 1:If a transversal intersects two PARALLEL Lines then each pair of alternate INTERIOR angles is equal.

Theorem 2 :If a transversal intersects two lines such that a pair alternate interior angle is equal then the two lines are parallel. 


SOLUTION:

Given:  ∠AGE=126°

∠AGE=∠GED=126∘ [alternate interior angles]


 (ii) ∠GED=∠GEF+∠FED=126∘

∠GEF + 90° =126°

(GIVEN that EF⊥CD) 

∠GEF=126°−90°=36°

∠GEF=36°


(iii) ∠CEG+∠GED=180°

(GIVEN ∠GED=126∘)

∠CEG+126° =180°

∠CEG=180° −126°

∠CEG=54°

∠FGE=∠CEG= 54°     (alternate angles)


HOPE THIS WILL HELP YOU...

15.

Prime minister of USA

Answer»

The HONORABLE Donald J. Trump. 
The USA uses a PRESIDENTIAL system of government, which MEANS Trump is both head of government and head of state.

16.

In the adjacent figure, a line n falls on lines l and m such that the sum of the interior angles 1 and 2 is less than 180°, then what can you say about lines l and m.

Answer»

They will intersect at one point when they are produced in the DIRECTION of GIVEN interior ANGLES.

17.

Which of the following is not a result of deforestation ?a.soil erosion b.flood c. droughtd.forest fires.

Answer» FORESTFIRE is not a RESULT of DEFORESTATION
18.

The sum of four consecutive even number is 156 find the number

Answer»

Let the FIRST even integer be x
Therefore
x+(x+2)+(x+4)+(x+6)=156
4x+12=156
4x=144
x=36
Therefore the four even integer are 36, 38, 40AND 42


HOPE IT 'LL BE HELPFUL FOR U

PLZZ... MARK IT AS THE BRAINLIEST

19.

The area of a triangle is 90 cm square if its base is 15 cm find its altitude

Answer» BASE = 15 CM

Area = 90 cm^2

=> Base × Altitude / 2 = 90

=> 15 × Altitude = 180

=> Altitude = 12 cm
20.

The four angles of a quadrilateral are in the ratio 1: 2:3:4. Find the measure of each angle of the quadrilateral.

Answer»

Solution

Given :

The ratio's of quadrilateral

1 : 2 : 3 : 4

                                         

To FIND :

MEASURE of each ANGLE of

quadrilateral.

                                         

Let the measures of angles

be x, 2x, 3x, and 4x

                                         

\therefore x+2x+3x+4x=360^\circ\\\\\implies10x=360^\circ\\\\\implies x=\dfrac{360}{10}\\\\\impliesx=36^\circ

                                         

Now we have the value of

'x' which is 36°

                                         

When we put the value of

'x' we get measure of all

angles of quadrilateral.

                                         

Let us do it,

Measure of angle First

= x = 36°

                                         

Measure of angle second

=2x

= 2  × 36

= 72°

                                         

Measure of angle third

= 3x

= 3 × 36

= 108°

                                         

Measure of angle FOURTH

= 4x

= 4 × 36

= 144°

                                         

Therefore measure of all

angles of quadrilateral is

36°, 72°, 108° and 144°

         

21.

Find the least number which when divided by 20, 30 , 40 leaves a remainder of 7 in each case.

Answer»

2 |20,30,40
2 |10,15,20
2 |5,15,10
5 |5,15,5
|1,3,1 Least Common MULTIPLE of 20,30,40 is 120. remainder is GIVEN as 7.So ANSWER is 120+7=127.

22.

Solve the following pair of linear equation by cross multiplication method first X + 2 Y is equal to 2 second x minus 3 Y is equal to 7

Answer»

X+2y=2 x-3y=7 ATQ x+2y+x+3y=7+2=9 2x+5y=9

23.

I am am the smallest number ,having four different prime factor. can you find me

Answer» HEY Mate

Here is your answer

To be number SMALLEST, FACTORS must also be smallest
4 different smallest PRIME factors are 2, 3, 5, 7
So the number is 2*3*5*7 = 210

Hope it helps

Plz MARK as Brainliest
24.

In the adjacent figure PQ and RS are two mirrors placed parallel to each other. An incident ray AB strikes the mirror PQ at B, the reflected ray moves along the path BC and strikes the mirror RS at C and again reflected back along CD Prove thatAB || CD. [Hint : Perpendiculars drawn to parallel lines are also parallel.]

Answer»

Alternate angles:When two lines are crossed by ANOTHER line the pair of angles on opposite sides of the transversal is called alternate angles.

 Theorem 1 : If a transversal intersects two Parallel Lines then each pair of alternate INTERIOR angles is equal.

Theorem 2 : If a transversal intersects two lines such that a pair alternate interior ANGLE is equal then the two lines are parallel.


SOLUTION:

Construction: Draw ray BE⊥PQ & ray CF⊥RS. BE⊥PQ, CF⊥RS & PQ || RS.

 ∴BE || CF

∠EBC=∠FCB     ……(i)     (Alternate interior angles) 

∠ABE=∠EBC ………(II)       (angle of incidence= angle of reflection) 

∠FCB=∠FCD  ……….(iii)       (angle of incidence = angle of reflection). 

From (i), (ii) and (iii),

∠ABE=∠FCD….(iv) 


Adding (i) and (iv), we get

∠EBC+∠ABE=∠FCB+∠FCD


∠ABC=∠BCD

But these are alternate interior angles and they are equal.Hence, AB || CD 

[fig. is in the attachment]


HOPE THIS WILL HELP YOU...

25.

बघू किती हुशार आहे आपला गृप 0२४ तासात उत्तर द्या... Total Marks 10 १ नंबर उत्तर देणारा होईल टँलेन्टेड नं 1 एका माणसाला, त्या दिवशी जी तारीख असेल तेवढे पैसे खर्च करण्याची सवय असते. (उदा. 18 तारखेला 18 रुपये.) एकदा त्याचे सलग 5 दिवसाचे 63 रुपये खर्च झाले, तर ते 5 दिवस कुठले होते ?(तारखा सांगा) Best Of Luck Time starts now...

Answer»

Hey USER

Here is your ANSWER :-

तर ते पाच दिवस पुढीलप्रमाणे आहेत :-

28 फेब्रुवारी
29 फेब्रुवारी
1 मार्च
2 मार्च
3 मार्च

लीप वर्षाच्या तारीखा आहेत .

28 + 29 + 1 + 2 + 3 = 63 .

26.

How much water will a tank hold if the interior diameter of the tank is 1.6 m and its depth is 0.7 m?

Answer»

It will HOLD WATER EQUAL to its volume

= 2\pi \: r \: h \\  = 2 \times  \frac{22}{7}  \times 0.8 \times 0.7 \\  = 2 \times 22 \times 0.8 \times 0.1 \\  = 2 \times 17.6 \times 0.1 \\  = 2 \times 1.76 \\  = 3.52 {m}^{3}
mark as BRAINLIEST if HELPED

27.

The opposite side of quadrilateral are parallel.if one angle of quadrilateral is 60 find other angle

Answer»

Opposite sides PARALLEL means opposite ANGLES EQUAL.

so, If ONE angle =60°

opposite angle=60°

two angles left are ALSO equal. then 360-120=240°

240°÷2=120°

Other angles are of 120°

28.

27/5 + 33/4 - 19/3 is equal

Answer» UR ANSWER is 41/5 FINALLY DONE.
29.

An item is sold for rs 680 by allowing a discount of 15% on its marked price.the market price of item is

Answer» LET the MARKED price be be a

DISCOUNT = 15 % of a = 15a/100

Cost price = Marked price - Discount

=> 680 = a - 3a/20

=> 680 = 17a/20

=> a = 680 × 20 / 17

=> a = 40 × 20

=> a = 800

Marked price = Rs 800
30.

Which of the following can be the sides of a right triangle?(i) 2.5 cm, 6.5 cm, 6 cm(ii) 2 cm, 2 cm, 5 cm(iii) 1.5 cm, 2 cm, 2.5 cmIn the case of right-angled triangles, identify the right angles.

Answer»

I) as you can see 2.5^2+6^2=6.5^2
L.h.s=2.5^2+6^2
= 6.25+36
=42.25
=6.5^2=r.h.s
THEREFORE right ANGLE triangle
2) 2^2+2^2=8 and 5^2=25
They are not EQUAL, therefore not right angle triangle
3) 1.5^2+2^2=2.25+4
=6.25
=2.5^2
Therefore it is a right angle triangle

31.

Solve the following equation and verify your answer 2x+3/1/3x-1 = 3/5

Answer»

Answer:

The  VALUE of x=-2.

Step-by-step EXPLANATION:

Given : Equation \frac{2x+3}{\frac{1}{3}x-1}=\frac{3}{5}

To FIND : Solve the equation and verify ?

Solution :

\frac{2x+3}{\frac{1}{3}x-1}=\frac{3}{5}

CROSS multiply,

5(2x+3)=3(\frac{1}{3}x-1})

10x+15=x-3

10x-x=-3-15

9x=-18

x=-\frac{18}{9}

x=-2

The  value of x=-2.

Verification,

SUBSTITUTE x is LHS,

LHS=\frac{2(-2)+3}{\frac{1}{3}(-2)-1}

LHS=\frac{-4+3}{\frac{-2}{3}-1}

LHS=\frac{-1}{\frac{-2-3}{3}}

LHS=\frac{-1}{\frac{-5}{3}}

LHS=\frac{-1\times 3}{-5}

LHS=\frac{3}{5}

LHS=RHS

Hence verified.

32.

Prove that sinA.sin2A+sin3A.sin6A/sinA.cosA+sin3A.cos6A=tan5A

Answer»

HEYA MATE,

HERE IS UR ANSWER.

Thanks for asking this QUESTION.

sin A sin 2A + sin 3A sin 6A/ sin A cos 2A + sin 3A cos 6A = tan 5A

We will use the following formulae in this solution--

(1) Sin A . Sin B = (1/2) [ Cos (A-B) - Cos (A+B) ]
(2) Sin A Cos B = (1/2) [ Sin (A+B) + Sin (A-B) ]
(3) Sin A + Sin B = 2 Sin (1/2) (A+B) . Cos (1/2)(A-B)
(4) Sin A - Cos B = 2 Sin (1/2) (A-B) . Cos (1/2)(A+B)
(5) Sin ( -x ) = - Sin x
(6) Cos ( - x ) = Cos x

Solution --

Numerator = (1/2) [ 2 SinA Sin 2A + 2 Sin 3A. Sin 6A ] --- Use formula (1)

=> (1/2) [ Cos (A-2A) - Cos (A+2A) + Cos (3A-6A) - Cos (3A+6A) ]

=> (1/2) [ Cos A - Cos 3A + Cos 3A - Cos 9A ]

=> (1/2) [ Cos A - Cos 9A ] .... Again use formula (1)

=> Sin 5A . Sin 4A

Denominator

= Sin A Cos 2A + Sin 3A.Cos 6A

=> (1/2) [ Sin (A+2A) + Sin (A-2A) + Sin ( 3A + 6A ) + Sin ( 3A - 6A ) ]

=> (1/2) [ Sin 3A - Sin A + Sin 9A - Sin 3A ]

=> (1/2) [ Sin 9A - Sin A ]

=> (1/2) [ 2 Cos 5A . Sin 4A ]

=> Cos 5A . Sin 4A

Hence the Left HAND Side of the given identity

= Numerator / Denominator

=> Sin 5A . Sin 4A / Cos 5A . Sin 4A

=> Tan 5A = RHS ………………. QED .

I HOPE IT HELPS U.

33.

Find K, if the sum of the zeroes of the polynomial x2 -(k+6) x + 2 (2k-1) is half their product.

Answer»

K+6)/1=2(2k-1)/2
k+6=2k-1
2k-k=6+1
k=7

34.

An expression to convert 50 miles per hour to miles per minute is shown.

Answer»

Hi ,

***************************************

We KNOW that ,

1 hour = 60 MINUTES

***************************************

50mile/hour

= 50 miles / ( 60 minutes )

= ( 5/6 ) miles per minute

I hope this helps you.

: )

35.

What will be the product if we multiply the double of 137 bu the triple of 2000

Answer» ANS of your QUESTION is 1644000
36.

a number n when divided by 15 gives the remainder 4 then what is the remainder when the same number is divided by 5

Answer»

N/15=4
n=15×4
n=60

n/5=?

we KNOW that n=60

so,60/5=x

x=12

The REMAINDER is 12
plz MARK as BRAINLIEST

37.

Umesh set up a new factory by investing rs 40,000. During the first three successive years his profits were 5%,10%&15%respectively. If each year the profit was on previous years capital, calculate his total profit

Answer»

HOPE this will HELP you

38.

In a quadrilateral ABCD the measure of three angles A, B, C are 110?, 70, 80 degrees then find the measure of the fourth angle D

Answer»

We know that the sum of all angles of a quadrilateral is EQUAL to 360
Then....
=> A+B+C+D=360
=> 110+70+80+D=360
=> 260+D=360
=> D =360-260
=> D =100

HOPE THIS WILL HELP U
♥️ PLEASE MARK AS BRAINLIST ♥️

39.

Is it possible to construct a quadrilateral abcd in which ab=5cm,bc=7.5cm,anglea=80°,angle b=140°and angle c =145°. if not give reason?

Answer»

I THINK this IMAGE will HELP you

40.

If 15 pens costs rs.90..then what will be the cost of 22pens?

Answer»

If 15 PENS costs rs.90..then what will be the cost of 22pens? mujhe lagta HAI YE sahi hai after all yhis is your CHOICE

41.

The sum of the 2nd term and the 7th term of an ap is 30. If its 15th term is 1 less than twice of its 8th term, find the ap

Answer»

Here is your solution

GIVEN:-

t2+t7=30
=>a+d+a+6d=30
=>2a+7d=30..................... (1)

A/q
15th term=2×8th term-1
=>a+14d=2×(a+7d)-1
=>a+14d=2a+14d-1
=>14d-14d+1=2a-a
=>1=a

Putting the value of a in EQUATION (1)

2a×7d=30
2×1+7d=30
2+7d=30
7d=30-2
7d=28
d=4

A.p are a,a+d,a+2d,a+3d,a+4d

=>A.p are 1,5,9,13.........

HOPE IT HELPS YOU

42.

To start a business Shalaka has taken a loan of `8000 at a rate of 10 1/2 p.c.p.a. After two years how much compound interest will she have to pay?

Answer»

Hi ,

It is given that ,

PRINCIPAL ( P ) = Rs 8000

Rate of interest ( R ) = 10½ % p.a = 21/2 yrs

Time ( T ) = 2 years

number of times interest paid = n = 2

Amount = A

A = P( 1 + R/100 )ⁿ


A = 8000 ( 1 + 21/200 )²


A = 8000 ( 221/200 )²


A = ( 8000 × 48841 )/ 40000

A= Rs 9768.20

Compound Interest ( C . I ) = A - P

= Rs 1768.20

I hope this HELPS you.

: )


43.

a boy reads 1/4 of a book on the first day. ob the second day he reads 1/3 of the remaing portion. what portiin of the book does the boy read in the two days ? if 100page are to be read , find how many pages are there in the book.

Answer»

Part of book read by boy on 1st day =1/4
So REMAINING part of the book = 1 - 1/4 = 3/4
Part of book read by boy on 2ND day = 1/3 × 3/4 = 1/4
Total part of book read by boy in TWO days = 1/4 + 1/4 = 2/4 = 1/2

Left part of the book = 1/2
According to question
100 PAGES are left
So, 1/2 = 100 pages
So, total pages in book= 2 × 100 = 200 pages

44.

If 1 upon 3 of a number exceeds its 2 upon 7 by 1 find the number

Answer» LET the NUMBER be X.

1/3 of x= x/3 

EXCEEDS its 2/7 i.e. 2x/7 by 1

Therefore x/3=2x/7+1

= x/3=2/7+7/7

=7x=6x+21

= x= 21

45.

If we have to write 3 numbers from 3 to 6 then will 3 or 6 would be included...urgent...tmrw exam

Answer» YES, both will be included
the NUMBERS are 3,4,5,6
46.

(2a-3b)³,Expand it, using suitable identities.

Answer»

Here is your ANSWER...

47.

The hcf of three numbers 8. The sum of the numbers is 80. List the passible sets of such thres number.

Answer»

The REQUIRED numbers can be 8,32,40 as their hcf is 8 and sum is 80

I think it is now CLEARED to you..............

PLZ MARK my ans as brainliest


48.

Sin.sqA=2sinA find the value of A

Answer»

I HOPE it can HELP you and MAKE it BRAINLIST

49.

One fourth of a number exceeds one fifth of the number by 4.Find the number.rnIF U GIVE THE ANSWER (ONE THUMPS UP)

Answer» LET the REQUIRED number be ( K ),



According to the question,




1 / 4 of k = 1 / 5 of k + 4

\frac{k}{4}  =  \frac{k}{5}  + 4 \\  \\  \\  =>  \frac{k}{4}  -  \frac{k}{5}  = 4 \\  \\  =>  \frac{5k - 4k}{20}  = 4 \\  \\  \\  = > k = 80



Required number is 80
50.

The students in three sections are in the ratio 2:3:5 if 12 students are increased in each section the ratio changes 4:5:7 what was the total number of students in the three sections before the increase

Answer»

Let the total NUMBER of students be x.

Let the sections be A, B and C.

The ratios are :

2 : 3 : 5 respectively

The sum of the ratios is 2 + 3 + 5 = 10

The number of students in section :

A = 2/10x

B = 3/10x

C = 5/10x

When 12 students are added in each section we have :

A = 2/10x + 12

B = 3/10x + 12

C = 5/10x + 12

The new ratios of A : B : C is :

4 : 5 : 7

This is equal to :

(2/10x + 12) : (3/10x + 12) : (5/10x + 12) = 4 : 5 : 7

(2/10x + 12) : (3/10x + 12) = 4 : 5

(2/10x + 12) / (3/10x + 12) = 4/5

5{2/10x + 12} = 4{ 3/10x + 12}

x + 60 = 12/10x + 48

10x + 600 = 12x + 480

12x - 10x = 600 - 480

2x = 120

x = 60

The total number of students in the three sections before more students were added is thus 60