Answer:
Step-by-step explanation:
Use the formula,
Distance = Speed x Time
David
Distance = 10 miles x 1/2 hour = 5 miles (half of 10)
Cindy
Distance = 14m x 1 1/2 hours
= 14m x 3/2 hours = 21m (or for 1 hour its 14m and for 1/2 it's half of 14 which is 7. Then for 1 1/2, add 14 and 7, which is 21.)
Julia
Distance = 8km x 3 1/2 hours
= 8km x 7/2 hours = 28km