Q: Elmer has a pond that initially contained 2400 pollywogs, but these pollywogs matured into toads and left the pond at a constant rate of 50 pollywogs per day. In addition, Elmer has a son named Melvin, who loves to catch pollywogs, remove them from the pond, and release them into a nearby stream. For the first 20 days, Melvin caught 10 pollywogs per day and released them into the stream. How many days did it take for all of the pollywogs to disappear from the pond?
A: 44
Step-by-step reasoning process: For the first 20 days, the combined rate of disappearance of pollywogs from the pond is 50 + 10 = 60 pollywogs per day. During these first 20 days, the total number of pollywogs removed was 60 * 20 = 1200 pollywogs. This means after 20 days there were 2400 - 1200 = 1200 pollywogs left in the pond. At a disappearance rate of rate 50 pollywogs per day, it will take an additional 1200 / 50 = 24 days for the rest of the pollywogs to disappear from the pond. Thus, overall, it will take 20 + 24 = 44 days for all of the pollywogs to disappear from the pond.

Q: A Ferris wheel can accommodate 70 people in 20 minutes. If the Ferris wheel is open from 1:00 pm until 7:00 pm, how many people will get to ride?
A: 1260
Step-by-step reasoning process: The Ferris wheel will be open for 7:00 - 1:00 = 6 hours. In one hour the wheel can ride 60 minutes / 20 minutes = 3 times the number of riders. The total per hour riders is 3 * 70 people = 210 people. If the ride is open 6 hours * 210 people = 1260 people can ride.

Q: Mary has 400 sheep on her farm. She gave a quarter of her sheep to her sister, and half of the remaining sheep to her brother. How many sheep remain with Mary?
A: 150
Step-by-step reasoning process: Mary gives 1 / 4 * 400 = 100 sheep to her sister. She now has 400 - 100 = 300 sheep remaining. She then gives 1 / 2 * 300 = 150 sheep to her brother. So 300 - 150 = 150 sheep remain.

Q: Vinny weighed 300 pounds then lost 20 pounds in the first month of his diet. He continued his diet but each month, he lost half as much weight as he had lost in the previous month. At the start of the fifth month of his diet, he worked harder to lose extra weight then decided to end his diet. If Vinny weighed 250.5 pounds at the end of his diet, how many pounds did he lose throughout the fifth month?
A: 12
Step-by-step reasoning process: In the second month, Vinny lost half as much as he had the first month, so he lost 20 pounds / 2 = 10 pounds. In the third month, he again lost half as much which was 10 pounds / 2 = 5 pounds. And in the fourth month, he lost 5 pounds / 2 = 2.5 pounds. So in total, Vinny lost 20 + 10 + 5 + 2.5 = 37.5 pounds in the first four months. Over his entire diet, he had lost 300 250.5 = 49.5 pounds. So in the fifth month, Vinny must have lost 49.5 pounds total loss 37.5 pounds loss in the first four months = 12 pounds.