InterviewSolution
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InterviewSolution
| 1. |
If mean of 20 numbers is 18,if 20 is added in each number so find new mean |
| Answer» observations be x1, x2, x3,.......,x8, x9, x10, x11, x12,..........,x20.We know that,Sum of n observations = Mean × Number of observation, n∴ Sum of 20 observation = 18 × 20 ⇒ x1+ x2 + x3 +.......x8 + x9 + x10 + x11 + x12 +..........+x20 = 360 ...(1)when 20 is added to 20 observation, thenSum of new observations= (x1 + 20) + (x2 + 20) + (x3 + 20) +......+ (x8 + 20) + (x9 + 20) + (x10 + 20) +( x11 + 20) + (x12 + 20) +..........+ (x20 + 20).= (x1 + x2 + ...... + x20) + 20 × 20= 360 + 400 (Using (1))= 760. | |