CA Foundation · Quantitative Aptitude · Sequence and Series
Five arithmetic means are inserted between 7 and 43. What is the third arithmetic mean?
The third arithmetic mean is 25. Inserting five means gives seven terms with six equal steps, so d = (43 - 7)/6 = 6. The means are 13, 19, 25, 31 and 37, so the third is 25.
- A25Correct
- B31
- C19
- D28
Explanation
With 5 means there are 7 terms, so 43 = 7 + 6d, giving d = 6. The means are 13, 19, 25, 31, 37, and the third is 25. Using d = 36/5 by treating it as 5 steps gives a wrong result, and 31 is the fourth mean.
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