Question

The mean of 12 numbers is 7 .if 2 is added to each number,what will be the new mean?

Answer 1

Given, there are 12 numbers
Mean = 7.Let their sum be x.
So mean = x/12=7.
If two is added to each number then the sum increases by 12*2 = 24. So,
for finding the new mean we'll divide it by 12
∴ Mean = (x+24)/12⇒
(x/12+24/12)

We know , x/12=7
7+ 2 = 9

So, the required new mean is 9.