number 9 and 10 pls help

9A. How long does it take to go 1000 miles at a speed of r miles per hour?
9B. It 75 degrees in a new refrigerator and the temperature is predicted to drop at 3 degrees per minute when it's turned on. What's the temperature after m minutes?
9C. Joe has $30 and make $2 per day. How much does he have after d days?
10. Start at 35,000 and descend 2,500 feet per minute for m minutes:
35000 - 2500 m
Answer: choice C