Question

The average of 5 numbers is 50, the average of 10 numbers is 30 and the average of 15 numbers is 20. Find the average of 30 numbers.

Answer 1

Sum of 6 numbers =60×30=180

Sum of first 4 numbers =4×25=100

Sum of last 3 numbers =3×35=105

∴ Fourth number =(100+105)−180

                               =205−180

                               =25

Answer 2

Answer:

the answer for the above sum is 25//