Letting

, we get

and

, so we can parameterize the intersection by

where

.
Image attached.
No. which have factors 2 & 5 have 2 & 5 as their prime factor
therefore, No. are :
2*5 = 10
2*5*2 = 20
2*5*3 = 30
Answer is c
something that helps me is
soh- opposite hypotenuse cah - adjacent and hypotenuse toa- opposite and adjacent
soh cah toa
He multiplied rather than dividing.

Hope this helps!
There are about 32 cups in a gallon.