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WAEC Further Mathematics 2017 Question 28

Question 28

Statistics

In a class of 10 boys and 15 girls, the average score in a Biology test is 90. If the average score for the girls is x, find the average score for the boys in terms of x.

  1. A.200 − (2/3)x
  2. B.225 − (3/2)x
  3. C.250 − 2x
  4. D.250 − 3x
Show the answer and explanation

Answer: B (225 − (3/2)x)

Explanation

Total = 25 × 90 = 2250. Boys' total = 2250 − 15x, so their average is 225 − (3/2)x.