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JAMB Mathematics 1989 Question 48

Question 48

Measures of Central Tendency

In a family of 21 people, the average age is 14 years. if the age of the grandfather is not counted, the average age drops to 12 years. What is the age of the grandfather?

  1. A.35years
  2. B.40 years
  3. C.42 years
  4. D.54 years
Show the answer and explanation

Answer: D (54 years)

Explanation

Total age = 21 × 14 = 294. Without him, 20 × 12 = 240. The grandfather is 294 − 240 = 54 years old.