Help for Exercises 47-49 on page 660
For Exercise 47, you are asked to find the rate at which gas is consumed. Suppose a car drives at a speed of
50 miles per hour. How many hours does it take to drive 1 mile?
So, it takes 0.02 hours to travel 1 mile. Notice that the final answer is a small number. This makes sense because it
doesn't take long to travel one mile at a rate of 50 miles per hour. Use a similar method to complete Exercise 47.
For Exercise 48, refer to the answer you found in Exercise 47.
For Exercise 49, you are asked to identify the type of variation. Direct variation equations are of the form
= k or y=kx where
k is a constant not equal to zero. Inverse variation equations are of the form xy=k or y=
where k is a constant not equal