Question

a coffee shop collected the following information regarding purchases from 120 of its customers. 59 purchased coffee. 40 purchased donuts. 19 purchased coffee and donuts. complete parts a) through c). a) of those surveyed, how many purchased only coffee? (type a whole number.)

Explanation:

Step1: Use set - theory principle

Let \(A\) be the set of customers who purchased coffee and \(B\) be the set of customers who purchased donuts. We know \(n(A\cup B)=120\), \(n(A) = 59\), \(n(B)=40\) and \(n(A\cap B)=19\). The number of customers who purchased only coffee is \(n(A)-n(A\cap B)\).

Step2: Calculate the number

We substitute the values into the formula: \(59 - 19=40\).

Answer:

40