Averages · Question 29 · Hard
Averages question 29
Of four numbers, the average of the first three is 16 and the average of the last three is 15. If the last number is 18, what is the first number?
- 21
- 15
- 19
- 24
Answer and explanation
Answer: A. 21
Explanation: First + (middle two) = 48 and (middle two) + last = 45. Subtracting, first − last = 3, so first = 18 + 3 = 21.
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