Answers

2016-03-30T19:08:13+05:30
If mean of 20 observations is 75
then the sum of 20 observations is 75 × 20 = 1500

if each observation is divided by 3
so 1500 will also be divided by 3
therfore 1500 ÷ 3
= 500
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2016-03-30T19:34:06+05:30
Mean of 20 observations = 75
Sum of 20 observations = 75×20=1500
New sum = 1500÷3=500
New mean = 500÷20=25
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