Let present age of B be X year's.

Present age of A = 4 × Present age of B = 4X year's.

Before 10 year's age of A = Present age of A - 10 = ( 4X - 10) year's.

Before 10 year's age of B = Present age of B - 10 = ( X - 10 ) year's .

According to question,

Before 10 year's age of A = 10 ( Before 10 year's age of B ).

4X - 10 = 10 ( X - 10)

4X - 10 = 10X - 100

10X - 4X = -10 + 100

6X = 90

X = 90/6

X = 15 year's.

Present age of B = X = 15 year's.

Let B be x years old.

.

Now:

B = x

A = 4x

.

Ten years ago,:

B = x - 10

A = 4x - 10

.

Ten years ago, A was 10 times as old as B:

4x - 10 = 10 (x - 10)

.

Solve x:

4x - 10 = 10 (x - 10)

4x - 10 = 10x - 100

10x - 4x = 100 - 10

6x = 90

x = 15

.

Find their present age:

B = x = 15

A = 4x = 4(15) = 60

.

Answer: B is 15 years old.

present age of B = 15 years old

Let present age of B be 'x' yrspresent age of A is 4x yrsTen years agoA's age= 4x-10B's age= x-10According to question4x-10=10(x-10)4x-10=10x-10010x-4x=100-106x=90x=90/6x=15therefore age of B=15 years

age of the B= 15 yrs is the correct answer of the given question



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Secondary School

Math

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A is four times as old as B. Ten years ago, A was 10 time as old as B. find the present age of B

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byAyanhusain04.08.2018

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Panzer786

Genius

Heya !!

Let present age of B be X year's.

Present age of A = 4 × Present age of B = 4X year's.

Before 10 year's age of A = Present age of A - 10 = ( 4X - 10) year's.

Before 10 year's age of B = Present age of B - 10 = ( X - 10 ) year's .

According to question,

Before 10 year's age of A = 10 ( Before 10 year's age of B ).

4X - 10 = 10 ( X - 10)

4X - 10 = 10X - 100

10X - 4X = -10 + 100

6X = 90

X = 90/6

X = 15 year's.

Present age of B = X = 15 year's.

present age of B=15 years answer.