A jar contains 3 red marbles, 5 green marbles, and 7 black marbles. First, a marble is taken and put into the jar again. Then another marble is drawn.

Question

 What is the probability of choosing a red marble and a black marble?

A. 3/7
B. 1/21
C. 7/75
D. 1/10

Answer 1

P(A and B)=P(A)*P(B) , probability of events A and B occuring at the same time.

 

P(red)=3/(3+5+7) or 3/15 or 1/5

 

P(black)=7/15

 

P(red and black)=(1/5)*(7/15) or 7/75

 

Choose choice C.