Ratio of boys and girls in college

CMAT 2021 · Quantitative Techniques & Data Interpretation · Easy · Ratio and Proportion

In June-2020, the ratio of boys to girls in a college was 3 : 2. In September-2020, there were 80 fewer boys and 20 fewer girls in the college and the ratio of boys to girls was 7 : 5. What was the total number of students in the college in June-2020?

  1. A.

    1000

  2. B.

    1100

  3. C.

    1200

  4. D.

    1300

Answer

D

Explanation

Let the number of boys and girls in June-2020 be 3x3x and 2x2x respectively.

In September-2020:

  • Number of boys = 3x−803x - 80
  • Number of girls = 2x−202x - 20

Given ratio: 3x−802x−20=75\frac{3x - 80}{2x - 20} = \frac{7}{5} 5(3x−80)=7(2x−20)5(3x - 80) = 7(2x - 20) 15x−400=14x−14015x - 400 = 14x - 140 x=260x = 260

Total students in June-2020 = 3x+2x=5x=5×260=13003x + 2x = 5x = 5 \times 260 = 1300.

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