1- getting the total cost:
We know that Me will pay:
$905 for parts and $499 for labor cost
This means that:
Total amount paid = price for parts + labor cost
Total amount paid = 905 + 499
Total amount paid = $1404
2- checking using inverse operation:
Assume Meg pays $1404 for her car repairs. This cost includes both the price of parts and the labor cost.
Given that the price of parts = $905:
labor cost = 1404 - 905 = $499
Hope this helps :)