Question

The average of n numbers x1, x2, x3......xn is A. If x1 is replaced by (x+a)x1, x2 is replaced by (x+a)x2 and so on. Find the new average.

Answer 1

So original average =A
$\frac{x1 + x2 + x3...... + xn}{n}$
New average
$\frac{(x + a)x1 + (x + a)x2 + (x + a)x3..... + (x + a)xn}{n}$
Now you take x+a common so u get
$\frac{(x + a)(x1 + x2 + x3 ...+ xn)}{n}$
So new average = (x+a)*A
Hope it helps
:)