Answer:
Brenna has to route 19 phone calls to spend a total of 88 minutes on the phone
Explanation:
The time Brenna has already spent on phone = 69 minutes.
Total time she is to spend on the phone = 88 minutes
So, the minutes left yet = 88 minutes- 69 minutes
= 19 minutes
Now, for each calls she routes, she spends 1 minute extra.
So, in 19 minutes duration she can route EXACTLY 19 calls.
Hence, Brenna have to route 19 phone calls to spend a total of 88 minutes on the phone.