A mall has three department stores, J C Penney, Macy’s, and Sears. A survey of 1452 people ...

A mall has three department stores, J C Penney, Macy’s, and Sears. A survey of 1452 people exiting the mall found that 348 made a purchase at J C Penney, 280 made a purchase at Macy’s, 272 made a purchase at Sears, 82 made a purchase at J C Penney and Macy’s, 93 made a purchase at J C Penney and Sears, 52 of them made a purchase at Macy’s and Sears, and 14 of them made a purchase at all three stores. 

a) How many people made a purchase at Sears but did not make a purchase at Macy’s? 

b) How many people made a purchase at exactly one of the three stores?