Answer:
.009 miles/hour
Step-by-step explanation:

This is the method you should take with unit conversions in general, just set up fractions so the units cancel out, like the 7.5 feet cancels out with the feet in the 1/5280 so miles is left on top.
You should have written like this
1 hour /16 = x hour /100
x=100/16=25/4=6.25
but it asks how many hours after first hour
6.25-1=5.25
Well, if both Alexis and Tara mine salt for 40 hours... they'd have mine 1,000 pounds of salt. Is this what you were looking for?
I think you posted this question more than once..
Im imperfect linear :( line grafh