Originally Posted by **d.darbyshire**

Suppose that a bag contains 6 red marbles and 5 yellow marbles. A single marble is picked at random out of the bag and is not put back in the bag; then a second marble is drawn at random out of the bag. Find

a. the probability that both marbles are yellow

b. the probabilty that the second marble is red

c. the probability that the second marble is red given that the first is red

d. the probabilty that the second marble is red given that the first is yellow.

I have to also attach a tree diagram with this problem and don't understand the multipliang and adding acrooss the diagram.

Please help. Thanks a million.