Question

if 10 numbers ka mean20 hai to every number se 2 subtract karne par new mean kya hoga

Answer 1

Heya,
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Mean = (x1 +x2 +x3----x10)/10

20  = (x1+x2+x3----x10)/10

20*10  =(x1+x2+x3--x10)


It Means the sum of 10 numbers is 200,
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If 2 is subtracted from each, it means that (2*10) is subtracted from sum of observations

Then, 

The sum of new observations is 200-20 =180 
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Now,

New Mean = (sum of new 10 observations)/10

New Mean  = (180/10)

New Mean = 18
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 i hope this will help you


-by ABHAY

Answer 2

Sum of 10 numbers=10×20=200
If 2 subtract from every number=200-2×10=180
Then new mean=180/10=18