Question

The students in three classes are in the ratio 4 : 5 : 3. If 30 students are increased in each class, the ratio changes to 6 : 7 : 5. The total number of students before the increase was:
1. 180
2. 240
3. 120
4. 96

Answer 1

Correct Answer - Option 1 : 180

Given: The ratio of students in the three classes is 4 : 5 : 3.

Let, the number of students is 4x, 5x and 3x.

Now, if 30 students are increased in each class then the ratio will be 6 : 7 : 5.

The new ratio will be:

→ (4x + 30) : (5x + 30) : (3x + 30) = 6 : 7 : 5.

→ (4x + 30) / (5x + 30) = 6/7.

→ 28x + 210 = 30x + 180.

→ 30 = 2x.

→ x = 30/2.

→ x = 15.

The total number of students before increase were (4x + 5x + 3x).

→ 12x.

→ 12 × 15.

→ 180.

As the total number of students before increase were "180".

Therefore, the correct answer should be "Option1: 180".