The first thing we must do for this case is to find the number of miles traveled during a day:
"3 miles around the school track and then half the distance on a treadmill"
Thus:
3 + (1/2) * (3) = 3 + 1.5 = 4.5 thousands
Then, an expression for the number of miles is:
f (D) = 4.5D
Answer:
an expression to show the number of miles Paul runs in D days is:
f (D) = 4.5D
