Jim was trying to cut down the number of miles he is running, because his knee hurts. Today, he ran 7 miles. He wants to reduce this to 3 miles. He decided that he would run 1/2 miles less each week than the week before.

a. Write an equation that could be used to solve for W, the number of weeks it would take Jim to go from running 7 miles to running 3 miles.

b. Solve the equation

c. Write your answer as a complete sentence