In Mr. Joe's class, 1/4 of the students failed the final exam. Of the remaining class, 1/3 scored an A. What fraction of the class passed but didnt get an A?

a)1/4

b)5/12

c)1/2

d)7/12

i got c) because I made the teacher have 100 kids, and 1/4 = 25 failed. then 75 (remaining) x 1/3= 25 got an A. The rest of them is 50 kids, and 50/100 = 1/2, so thats why i got c.

the answer is d. i tried working backwards but it didnt help.