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If the mean of 4 observations is 20, when a constant ‘C’ is added to each observation, the mean becomes 22. The value of C is :
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- 6
- –2
- 2
- 4
- 6
Correct Option: C
Given ,The mean of 4 observations = 20
Total of 4 observations = 20 × 4
When a constant ‘C’ is added to each observation, then
New mean = 22
Total of new observations = 22 × 4
⇒ 4C = 22 × 4 – 20 × 4 = 88 – 80 = 8
⇒ C = 8 ÷ 4 = 2
