Question

the average of three numbers is 30.the average of two of them is 20the third number is

Answer 1

H

Let a , b , c are three numbers ,

Average of 3 numbers = 30

( a + b + c ) /3 = 30

a + b + c = 90 -----( 1 )

Average of 2 numbers = 20

( a + b ) /2 = 20

a + b = 40 ----( 2 )

Subtract ( 2 ) from ( 1 ) we get ,

c = 90 - 40

c = 50

Therefore ,

Required third number = c = 50

I hope this helps you.

:)