Q37:
A jar contains 16 marbles, of which 4 are red, 3 are blue, and the rest are yellow. If 2 marbles are to be selected at random from the jar, one at a time without being replaced, what is the probability that the first marble selected will be red and the second marble selected will be blue?
A. 3/64
B. 1/20
C. 1/16
D. 1/12
E. 1/8
我是直接3/16乘以4/16算出来的，结果是A，但是正确答案是B，请问如何求出？ | 
