Maths : Basic Numeracy

Q 172 / 370

UPSC CSE Prelims 2021

In a class, 60% of students are from India and 50% of the students are girls. If 30% of the Indian students are girls, then what percentage of foreign students are boys?

EXPLANATION

Correct Option (D)

To determine the percentage of foreign students who are boys, we can assume a total number of students for calculation simplicity.

  • Let the total number of students in the class be 100.
  • Number of Indian students = 60% of 100 = 60.
  • Number of foreign students = Total students - Indian students = 100 - 60 = 40.
  • Total number of girl students = 50% of 100 = 50.
  • Number of Indian girl students = 30% of Indian students = 30% of 60 = 18.
  • Number of foreign girl students = Total girl students - Indian girl students = 50 - 18 = 32.
  • Number of foreign boy students = Total foreign students - Foreign girl students = 40 - 32 = 8.
  • The required percentage of foreign students who are boys = (Number of foreign boy students / Total foreign students) × 100 = (8 / 40) × 100 = 20%.

Incorrect Options:

Options A (45%), B (40%), and C (30%) are not consistent with the calculated percentage of foreign students who are boys. These values may arise from miscalculations or incorrect application of the given data points.