Question

The average of a set of 5 numbers is 10.A number 14 is deleted from the set. what is the average of the remaining four numbers.

Answer 1

let the no. be a,b,c,d,14
then (a+b+c+d+14)/5=10
a+b+c+d=50-14
now
(a+b+c+d)/4=36/4
therefore
average of remaining numbers will be 9

Answer 2

let 5 numbers be a + b +c +d+ e



Mean=a+b+c+d+e/number of terms
10=a+b+c+d+e/5
a+b+c+d+e= 10 * 5
a+b+c+d+e=50

Number 14 is deleted from set
= 50-14
=36

New mean =36/4
=9