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GATE 2021 CH – Question 1

General Aptitude · Quantitative Aptitude: Arithmetic and Number Computation · 1 mark · Multiple choice

The ratio of boys to girls in a class is 7 to 3. Among the options below, an acceptable value for the total number of students in the class is:

  1. 21
  2. 37
  3. 50
  4. 73

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Show answer and explanation

Correct answer: (C) 50

Explanation

The ratio $7:3$ is in its lowest terms, so the numbers of boys and girls must be $7k$ and $3k$, with $k$ an integer. Thus the total is $10k$, a multiple of 10.

Only 50 satisfies this condition: it gives 35 boys and 15 girls. The other totals would require fractional student counts. **Answer: C (50).**