Rudy runs 5 miles at a rate of 10 minutes per mile. Later he runs 4 miles at a rate of 9.5 minutes per mile. What is the total length of time that Rudy runs? Give the rationale and then the answer.
Let's think step by step. Rudy first runs for 5 * 10 = 50 minutes. Then Rudy runs for 4 * 9.5 = 38 minutes. Rudy runs for a total length of 50 + 38 = 88 minutes.. The answer is: 88.

Michael has 2 cats and 3 dogs. He needs to pay a friend to watch them, who charges $13 a night per animal. How much does Michael have to pay? Give the rationale and then the answer.
Let's think step by step. Michael has 5 animals because 2 + 3 = 5. Michael has to pay $65 because 5 x $13 = $65.. The answer is: 65.

If farmer Steven can use his tractor to plow up to 10 acres of farmland per day, or use the same tractor to mow up to 12 acres of grassland per day, how long would it take him to plow his 55 acres of farmland and mow his 30 acres of grassland? Give the rationale and then the answer.
Let's think step by step. At a rate of 10 acres per day, he can plow his 55 acres of farmland in 55 / 10 = 5.5 days. At a rate of 12 acres per day, he can mow his 30 acres of grassland in 30 / 12 = 2.5 days. Altogether, it would take him 5.5 + 2.5 = 8 days to completely mow and plow his land.. The answer is: 8.