Question

The number of students in three classes is in the ratio 3 : 13 : 6. If 18 students are added to each class, the ratio changes to 15 : 35 : 21

The total number of students in all the three classes in the beginning was:

1. 110
2. 22
3. 88
4. 66

Answer 1

Correct Answer - Option 3 : 88

Given:

The original ratio of student in three classes is 3 : 13 : 6

Calculation:

Let be assume the at the beginning students in three-class were 3x, 13x, and 6x respectively and after ratio was 15y, 35y, and 21y respectively.

⇒ 3x - 15y = -18 ..... (1)

⇒ 13x - 35y = - 18 .... (2)

By solving (1) and (2)

⇒ x/y = 2/1

⇒ From equation (1)

⇒ x = 4, y = 2

⇒ The total number of student in all classes = 3x + 13x + 6x = 22x = 22 × 4 = 88

∴ The required result will be 88.