The number of boys in a school is 400 more than the number of girls, i

1.	The number of boys in a school is 400 more than the number of girls, if the total number of students is 680 find the number of girls
Answer» Answer: CORRECT OPTION is A 20 As the ratio of boys to girls is 5:7 and the total number of students is 672, Number of boys = 5+7 5 ×672=280 And Number of girls = 5+7 7 ×672=392 Let the number of boys admitted be a. Then total number of boys =280+a As the number of girls increases by 8. total number of girls 392+8=400 Given, new ratio of boys to girls is 3:4 =>280+a:400=3:4 => 400 280+a = 4 3 On CROSS multiplying, 280+a= 4 3 ×400 280+a=300 =>a=20 So, the number of new boys admitted is 20.

The number of boys in a school is 400 more than the number of girls, if the total number of students is 680 find the number of girls

Answer»

Answer:

CORRECT OPTION is

As the ratio of boys to girls is 5:7 and the total number of students is 672,

Number of boys =

5+7

×672=280

And Number of girls =

5+7

×672=392

Let the number of boys admitted be a. Then total number of boys =280+a

As the number of girls increases by 8. total number of girls 392+8=400

Given, new ratio of boys to girls is 3:4

=>280+a:400=3:4

400

280+a

On CROSS multiplying,

280+a=

×400

280+a=300

=>a=20

So, the number of new boys admitted is 20.