The mean of the five numbers 8, 12, x, 15, and 21 is 14. Find the value of x.
Answer and explanation
Correct answer: A. 14
- Step 1: Mean formula: sum / count = mean => (8 + 12 + x + 15 + 21) / 5 = 14. Step 2. Multiply both sides by 5: 56 + x = 70. Step 3. Solve: x = 70 - 56 = 14. Answer: 14. Why not the others: 12 gives mean 13.6; 16 gives mean 14.4; 10 gives mean 13.2.
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