Final answer:
To determine the number of miles Aldo drove, subtract the base fee from the total cost and then divide by the cost per mile. The calculation reveals that Aldo drove the truck for 158 miles.
Step-by-step explanation:
The student asked how many miles Aldo drove the truck given that there was a base fee of $20.99 and an additional charge of 79 cents per mile, with the total cost being $145.81. To find the number of miles driven, we first subtract the base fee from the total cost:
Total cost - base fee = additional charges
$145.81 - $20.99 = $124.82
Now we divide the additional charges by the cost per mile to find the number of miles driven:
Additional charges / cost per mile = number of miles driven
$124.82 / $0.79 = 158 miles
Therefore, Aldo drove the truck for 158 miles.