Question

Joe's Electric made 17 customer calls last week and 24 calls this week. How many calls must be made next week in order to maintain an average of at least 19 calls per week for the three week​ period?

Answer 1

(16+24+x) / 3= 19
16 + 24+x =57
x=17

Answer 2

To average 19 calls for three weeks, they need to make 3x19 = 57 calls over the three weeks.

Since they've already made 17 and 24 (so a total of 41 calls), then need to make 57-41 = 16 more calls next week.