Please help i’m gonna fail

the answer is not D

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.

Find the value of x. round the length to the nearest tenth

True or false: the graph of y=f(bx) is a horizontal compression of the graph y=f(x) if b< 1