Answer:
$180
Explanation:
If in 7.5 hours you get $45 then add 7.5 and 7.5 to get 15 hours.
Now 15 + 15= 30 so because of that you can know that 7.5 times 4 gives you your 30 hours.
So now all you have to do is do 45 times 4 to get your end result of $180.