Answer:
7.2 km
Step-by-step explanation:
Distance between Brookfield to Seaside = 20.4 km
Distance between Yardley and Seaside = 13.2 km
Let distance between Brookfield to Yardley be x.
Thus:
x + 13.2 km = 20.4 km
Subtract 13.2 from each side
x = 20.4 - 13.2
x = 7.2
Distance from Brookfield to Yardley is 7.2 km
$10 / 6 = $1.67
total cost divided by number of books equals cost per book.