Algebra word problem

Question

If you are traveling in your car at an average rate of R miles per hour for T hours, then the distance, D, in miles, that you travel is described by the formula d=rt, that is, distance equal rate times time. Solve the formula for t. Use the formula in part (a) to fine the time that you travel if you cover a distance of 225 miles at an average rate of 50 miles per hour.

Answer 1

First, solve the formula for t  (get t by itself on one side of the equality)

 

If d=rt we can divide both sides of the equation by r in order to remove the r from the right side.

This gives us d/r=t

 

Now, substitute 225 for d and 50 for r and then solve for t.

 

This gives us 225/50=t.  Simplified, we get 4.5=t