Simplify and factories 16g + 32h - 48g - 40h

For this question you can say:
16g - 48g = -32g 
and 32h - 40h = -8h 
so you will have: 
-32g - 8h and you can factor -8 so you will have: 
-8(4g + h) :)))
i hope this is helpful 
have a nice day 

Graph a should be your answer

The answer would be 13.5 minutes.