Respuesta :

Solutions 

4 hr = 20 dollars

5 hr = 25 dollars

6 hr = 30 dollars

7 hr = 35 dollars

8 hr = 40 dollars

9 hr = 45 dollars

10 hr = 50 dollars 

To solve the problem you start at 4 ( Hours) and add 1 hour to it and the cost starts at 20 and add 5 to it. 
apologiabiology
goes up by 5 each time
7+3=10
3 tiems 5=15
35+15=50

$50=10 hours