1. The answer you put seems fine.
2. Also good.
3. The answer's right.
4. I got $2.45, not $2.42
5. 60/5 = 12 gallons / 1 minute 12 gallons per minute
6. 954/4.5 = 212 miles / 1 hour 212 mph
7. 111600/1200 = 1116/12 = $93 / 1 square foot $93 per square foot
8.
8 ounce box: 2.88/8 = $0.36 per ounce
12 ounce box: 3.60/12 = $0.30 per ounce
The 12 ounce box is the better buy
Good luck!