Answer: The least number of minutes that he has used his phone in a month is 1248
Step-by-step explanation:
Let m represent the number of minutes that he used his phone in a month.
For his phone service, Michael pays a monthly fee of $16, and he pays an additional $0.04 per minute if use. This means that if he used m minutes in a month, the total cost would be
16 + 0.04m
The least he has been charged in a month is $69.52. This means that
16 + 0.04m ≥ 65.92
0.04m ≥ 65.92 - 16
0.04m ≥ 49.92
m ≥ 49.92/0.04
m ≥ 1248 minutes
