Answer: 65000$ worth of things
This is edited, because I got it backwards last time.
We need to make 2500, but she only makes 4% of whatever she sells.
That means the equation is
2500 = 0.04x
Now, we just need to divide both sides by 0.04 and we get 65000.
Sorry for the confusion.
We have a ratio of 3 hours / 7.5 miles
We want to know how many miles he can walk in 1 hour so, divide both sides by 3 -> 1 hour / 2.5 miles
He is walking at 2.5 mph