CA Foundation · Quantitative Aptitude · Measures of Central Tendency and Dispersion
The mean of 5 numbers is 30. When a sixth number is added, the mean becomes 32. What is the sixth number?
The sixth number is 42. The first five sum to 5 × 30 = 150, and all six must sum to 6 × 32 = 192, so the added number is the difference, 192 − 150 = 42.
- A42Correct
- B36
- C38
- D40
Explanation
Sum of 5 numbers = 150. Sum of 6 numbers = 6 × 32 = 192. Sixth number = 192 − 150 = 42. Option 32 would be a mistake of just using the new mean; 36 is wrong as it adds 6 to 30 only.
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