Answer:
Given data:
A week has 168 hours So S is the work done by Stephanie and R is the work done by Robert in one week.
According to given conditions:
S = 12* 168 = 2,016
R = 15*168 + 18 = 2520 + 18 = 2,538
Now for total sales of week:
Total = S + R
By putting value:
Total = 2,016 + 2,538
Total = 4,554
So total of 4,554 pretzels will be sold by both.