Question

Ratio of boys to girls in a class is 7:9. Total strength of the class is 32. Number of girls in the class is
Options
O 15
0 20
o 17
O 18​

Answer 1

Given:

• Ratio of boys to girls is 7:9
• Total strength of the class is 32.

To find:

Number of girls in the glass?

Solution:

Let the ratio of boys be 7x

Let the ratio of girls be 9x

According to the question ;

$\red{\sf { 7x + 9x \implies \: 32}}$

$\red{\sf {16x \implies \: 32}}$

$\red{\sf {x \implies \: \frac{32}{16} }}$

Ratio of girls is = 9x

$\implies \: 9 \times 2 = 18$

∴ Girl's are 18 in the class.

Answer 2

Given:

The ratio of boys to girls is 7:9 and the total strength of the class is 32.

To find:

Number of girls in the class.

Solution:

As given in the question, the ratio of boys to girls is 7:9.

So, let 'a' be the common ratio between the number of boys and girls.

we have,

Number of boys in the class = 7a

and,

The number of girls in the class= 9a

The total strength of the class = total number of boys+ total number of girls.

So,

$7a + 9a = 32$

$16a = 32$

$a = 2$

Hence, the total number of girls is

$9a = 9 \times 2 = 18$

The number of girls in the class is 18.

So, the correct option is 18.