Question

The arithemetic mean of 3,15, and my number is 40. What is my number?

Answer 1

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Average of given n numbers X1,X2,.........,Xn is x= £xi/n

Let the my number be x

Given:- The average of 3,15,x is 40

£xi/n =40

3+15+x/3=40

Multiplying 3 both side

18+x=120

x=120-18

x=102

Hence, my number is 102