Question

The mean of 10 number is 55. If one member is included, there mean become 60. Find the included number.

Answer 1

Please check the attachment dear !

Answer 2

your answer is here

let the sum of numbers be x

by formula of arithmetic mean

X/total number of members= mean

X/10 = 55

the sum is = 550

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let the new sum be y

y/N = mean ( N = total number of members)

y/ 11 = 60

y = 660

the new sum = 660

the new number added = new sum - previous sum

= 660 - 550

= 110