Answer:
Her mother will donate $11.20
Explanation:
- $0.40 every 0.75 miles.
- 21 miles biked.
Step 1: Figure out how many 0.75 increments are in 21 miles.
21 ÷ 0.75 = 28
- There are 28 increments of 0.75 in 21 miles.
Step 2: Multiply 28 by $0.40
28 * $0.40 = $11.20