The first one one would 42x+500 for Bill. Becauseee Bill is going 50 feet per minute. And x is minute.
For Bill is would be just be 50x
50x=42x+500
-42x
8x=500
_ _
8 8
X=62.5
(Btw I am not 100 percent sure if this is how you would solve this. But this is better than nothing on your worksheet . Hope it’s right!)