The average of n numbers is 42 If 75 of the numbers are increased by 4 each and the remaining number...........

Quantitative Aptitude (CPO) Average

The average of n numbers is 42. If 75% of the numbers are increased by 4 each and the remaining numbers are decreased by 8 each,

then what is the average of the numbers, so obtained?

This questions was previously asked in

SSC CPO 9th Dec 2019 Shift-2

43.8

42.5

Let’s break this down step by step:

- Start with n numbers, average is 42, so total sum is 42n.

- 75% of n — that’s (3/4)n — each get increased by 4.

- Remaining 25% — that’s (1/4)n — each get decreased by 8.

- The net change? (3/4)n×4 = 3n; (1/4)n×(-8) = -2n. So, total change = 3n + (-2n) = n.

- New sum = 42n + n = 43n.

- New average = (43n) / n = 43.

Comparing the options:

- Option 1: 43.8 too high

- Option 2: 43 exactly matches

- Option 3: 42.5 too low

- Option 4: 44 even higher

So the clear answer is Option 2 (43).

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