Question

Q9: 80% of 120 students in a class
are boys. The number of girls in the
class is
O A: 24
O B:20
O
C: 15
O O
D: 30​

Answer 1

Given:-

80%of 120 students in a class =boys

To find:-

number of girls

Solution :-

Let's understand the concept:-

80%of 120 students in a class are boys so the rest are girls

First we need to find the percentage of girls.

${:}\longrightarrow$100%-80%=20%

Then we need to find the 20%of students for finding number of girls.

${:}\longrightarrow$20%of 120

$=120×{\frac{20}{100}}$

$={\cancel{120}}×{\frac{20}{{\cancel{100}}}}$

$=6×{\frac{{\cancel{20}}}{{\cancel{5}}}}$

$=6×4$

$={\underline{\boxed{\bf{24}}}}$

Hence your answer

$\odot{24}$

$\bigcirc{20}$

$\bigcirc{15}$

$\bigcirc{30}$

Answer 2

Given :

80% of 120 student in a class = boys

we have to find number of grils

Solution:

let's understand the concept

80% of 120 student in a class are boys so that rest are grils.

frist we need to find the percentage of girls

• 100% -80 = 20

then we need to find the 20% of students for finding number of grils

20% of 120

=120×20/ 10

=120×20/100 ( 120 and 100 cut )

=6× 20/5 ( 20 ÷5=4)

=6×4

=24

Hence your answer

A. 24 ✓

B. 20

C.15