Question

. A school has 630 students. The ratio of
the number of boys to the number of girls is
3 : 2. This ratio changes to 7 : 5 after the
admission of 90 new students. Find the
number of newly admitted boys.
​

Answer 1

let no. of boys and girls be 3x and 2x respectively

5x=630

x=126

therefore no. of boys and girls are 378&252 respectively.

similarly after admission of 90 students

12x=630+90

x=60

so after admission total no. of boys and girls will be 420 &300 respectively.

therefore no. of newly admitted boys =420-378=42