The mean of five numbers is 14. Four of the numbers are 10, 12, 15 and 18. What is the fifth number?
Answer and explanation
Correct answer: D. 15
- Step 1: The total of five numbers is 5 x 14 = 70.
- Step 2: The four known numbers total 10 + 12 + 15 + 18 = 55.
- Step 3: The fifth number is 70 - 55 = 15.
Answer
15.
Why not the others: 14 is the mean itself, 13 and 17 come from adding the four numbers wrongly.
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