Average 2011 PSLE

The average of A, B and C  is 5y. C has 2 y more than B and A has y more than B.
a) Find B. Give your answer in terms of y.
b) If y = 5, what is B?


A [][   2 y   ]    )
B []                  ) 5 y x 3 = 15 y
C [][ y ]            )

3 u  -->  15 y  -  2 y  -  y  =  12 y

1 u --> 12 y ÷  3  =  4 y

a) It was  4 y.


4 x 5 = 20

b) It was 20.