Answer:
D. 18
Explanation:
The ratio of boys to girls in Mr. Johnson's after-school club is the same as the ratio of boys to girls in Ms. Greene's after-school club.
There are 4 boys and 12 girls in Mr. Johnson's club.
There are 6 boys in Ms. Greene's club.
to get the number of girls in greene's club we represent it by x
and intrepret it in ratio
4:6 = 12: x
4/6 = 12/x
cross multiply
4x = 6 x12 = 72
x = 72/4 = 18
there are 18 girls in greene's club