Question

If the average of six numbers is 18 and the average of three of the numbers is 15, then what is the sum of the remaining three numbers?

Answer 1

a.
21
c.
53
b.
45
d.
63

Answer 2

\[\frac{ \sum~numbers }{ amount } = average \]

\[\frac{ 108 }{ 6 } = 18\]

if we've got 6 numbers and the average is 18 then the sum must be 108 because 108/6 = 18.

if the average of three of the numbers is 15 then

\[\frac{ 45 }{ 3} =15 \]

so to find out we do this:

108-43 = ?

Answer 3

@nickthurmm1