Mary remembers to take her purse with her only 3/4 of the time when she brings it into a store. She visits three stores in succession. She realizes that she had it when she entered the first store, but doesn't have it when she leaves the third. Find the probability that the umbrella is in each of the stores.
So after leaving the first store, the probability that it is in store 1 is 1/4. After leaving the second store, I calculated the probability that she had the purse with her after leaving the first floor, multiplied with the probability that she had the purse as she leaves the second store, which is 3/4 x 1/4 = 3/16. Is this method correct?