Which seven?
070,000,000 would be in the 10 millions
700,000,000 would be in the 100 millions
2x - y = 0
2x = y
3x - 2(2x) = -3
3x - 4x = -3
-x = -3
x = 3
2(3) = y
6 = y
There might be a variety of averages for the 12 boys.
The answer is 0.6 because you divide 21 by 35 and get 0.6