Answer:
60 minutes including the 15 minute rest.
Step-by-step explanation:
450/10 is 45. Therefore, biking for 45 minutes will loose 450 calories, 10 calories per minute. Maybe half way during the 45 minutes Spencer will take the 15 minute rest. This brings the biking trip 60 minutes.
Answer:

Step-by-step explanation:
19*19=361.
Answer:
2 hours or less depending on how skilled or how they're felling that day
Step-by-step explanation:
Answer:
idk but ask your teacher
Step-by-step explanation:
Answer:
might be 3
Step-by-step explanation: