Question

In a certain school,20% of students are below 8 years of Age.The Number of students obove 8 years of age is 2/3 of the number of students of 8 years of age which is 48.What is the total number of students in the school?​

Answer 1

Question:

In a certain school, 20% of students are below 8 years of age. The Number of students above 8 years of age is 2/3 of the number of students of 8 years of age which is 48.What is the total number of students in the school?​

Answer:

The number of students is 100.

Given:

20% of students are below 8 years of age

The Number of students above 8 years of age is 2/3 of the number of students of 8 years of age .

The number of students of age 8 years is 48.

To find:

The number of students in the school.

Explanation:

The number of students of age 8 years is 48.

The Number of students above 8 years of age is 2/3 of the number of students of 8 years of age .

∴ The number of students above 8 years age is_

(48×2/3)

= (16×2)

= 32 students.

∴ The number of students of either 8 years or more is_

(48+32) students

= 80 students.

Among the total  students, 20% students are of below 8 years old.

Let, the total number of students be, 'n'.

∴ The number of students of age below 8 years_

(n×20/100)

= n/5.

∴ The number of students of age either 8 or more_

(n$- \frac{n}{5}$)

$= (\dfrac{5n-n}{5})$ [ ∵ The L.C.M. of the denominators is 5.]

$= \dfrac{4n}{5}$

According to the problem:

$\dfrac{4n}{5} = 80$

⇒ 4n = (80×5)

⇒ 4n = 400

⇒ n = (400÷4)

⇒ n = 100 students.

∴ Total number of students in the school is 100.