Question

Two balls are drawn in succession out of a box containing 3 red and 4 white balls. Find the probability that the second ball was​ red, given that the first ball​ was:

​(A)  replaced before the second draw.
​(B)  not replaced before the second draw.

Answer 1

the answers to A- 3 out of 7 bc there are 7 balls total. and the answer to B- 3 out of 6 bc if the first ball drawn was not replaced, then there would only be 6 in the box. fraction forms- 3/7 and 3/6 (which can be reduced to 1/2)