Question

00: The ratio of girls in a school under 12 years and those over 12 years was 3 : 2 at the commencement of a term. At the end, the ratio was 2:3 as 30 girls had reached the age of 12 years during the term. Find the total number of girls in the school, assuming nobody left or was admitted during the term O 100 O 120 O 90 150 Next​

Answer 1

Answer:

Your correct answer is option D 150

Answer 2

We recall the concept of ratio

A ratio shows the  sizes of two or more values.

Given:

Initially The ratio of girls in a school under $12$ years and those over  $12$12years was$3:2$

At the end, the ratio was $2:3$

Thus we get,

$\frac{3x-30}{2x}=\frac{2}{3}$

$9x-90=4x$

$x=18$

Total no. of girls,

$=3x+2x\\=5x$

$=5*18\\=90$