Answer:
25%
Step-by-step explanation:
The price dropped by $7, because $28-$21=$7.
7/28 is 1/4. 1/4 in a percentage is 25%, because 1/4=25/100
240 miles
he drives 30 miles there and back which is 60 miles and 6 times 4 is 24 so 60 times 4 is 240
swimming: 0,75h
biking: 1,6h
running: 1h