Question

3. The average of 7 numbers is 12. The average of the 4 smallest numbers is 6 while the average of the

4 greatest numbers is 22. How much greater is the sum of the 3 greatest numbers than the sum of the 3
smallest numbers?

Answer 1

answer : d) 48


Given, the sum of 7 numbers=12*7=84
Sum of the 4 smallest numbers=4*8=32----(a)
Sum of the 4 greatest numbers=4*20=80 (here 3 numbers are different from the smallest numbers, one number is common to both smallest and greatest numbers)--(b)

To find:- sum of 3 greatest numbers-sum of 3 smallest numbers

3S+common number+3G+common number=80+32=112
=84+common number=112-84=28
So, common number=28

Now, from(a), 3S+common number=32
Or, 3S=32-28=4

from(b), 3G+common number=80
Or, 3G=80-28=52

So, 3G-3S=52-4=48

Where 3S and 3G denote the sum of 3 greatest numbers and sum of 3 smallest numbers respectively.

Ans. (D)