Use Bayes' theorem to find the indicated probability.
In the town of Maplewood a certain type of DVD player is sold at just two stores. 45% of the sales are from store A and 55% of the sales are from store B. 2.5% of the DVD players sold at store A are defective while 4.7% of the DVD players sold at store B are defective. If Kate receives one of these DVD players as a gift and finds that it is defective, what is the probability that it came from store A?