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JAMB Mathematics 2004 Question 10

Question 10

Sets

In a class of 40 students, each student offers at least one of Physics and Chemistry. If the number of students that offer Physics is three times the number that offer both subjects and the number that offer Chemistry is twice the number that offer Physics, find the number of students that offer Physics only.

  1. A.25
  2. B.15
  3. C.10
  4. D.5
Show the answer and explanation

Answer: C (10)

Explanation

Let x offer both. Physics = 3x, Chemistry = 6x, so 3x + 6x − x = 40 and x = 5. Physics only = 3x − x = 10.