Quantitative Reasoning – Practice – Stamp collecting club problem and 2 ways to solve it!


Ans: Average of 10 collections=88

Sum of the numbers= 880

55 was entered as 75; excess= 20

Also, 78 was entered as 88; excess=10

Total excess=30

Actual sum should be 880-30 = 850.

Actual average =850/10=85. Option E.

Another faster way to come to the result would be to notice that the excess 30 would bring about 30/10 (=3) increase in actual average. Since, average is gives as 88, actual average would be 88-3=85.

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