Q6:

The ratio of the number of red cars in a certain parking lot to the number of black cars is 3 to 8. If there are 72 black cars in the lot, how many red cars are there in the lot?

A. 11

B. 15

C. 24

D. 27

E. 32

我算的答案是27，答案却是24。请问我哪里做错了？

（3/8 = X/72 x=27）