To determine what effect the salespeople had on purchases, a department store polled 700 shoppers as to whether or not they had made a purchase and whether or not they were pleased with the service. Of those who had made a purchase, 120 were happy with the service and 119 were not. Of those who had made no purchase, 147 were happy with the service and 314 were not.

 Find

Probability that a shopper who was happy with the service had made a purchase
What can you conclude?