When 5 adults joined a group of y diners, the ratio of the number of adults to children in the restaurant became 3:5. Express the number of children in terms of y.

Answer 1

(A+5)/C = 3/5

5(A+5) = 3C

5A +25 = 3C

5A = 3C-25

A =3C/5 -5

A+C = y

3C/5 -5 +C =y

8C/5 = y+5

C = 5y/8 + 25/8

A+C = y

C=y-A = y- 3C/5 +5

C+3C/5 = y-5

8C/5 = y-5

C = 5y/8 -25/8

C(y) = (5/8)y - 25/8