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WAEC Mathematics 2009 Question 28

Question 28

Measures of Central Tendency

In an examination, Kofi scored x % in Physics, 50% in Chemistry and 70 % in Biology. If his mean score for the three subjects was 55 %, find x.

  1. A.40
  2. B.45
  3. C.55
  4. D.60
Show the answer and explanation

Answer: B (45)

Explanation

(x + 50 + 70)/3 = 55, so x + 120 = 165 and x = 45.