user: [Question]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?
[Answer]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. The answer is 44.
Q: In my school, the number of students has increased by 20% this year. The number of students this year is 960. How many students were there last year?
A: Let X be the number of students last year. The number of students this year is X + X * 20% = 960. Combining like terms, we get X * 1.2 = 960. Dividing both sides by 1.2, we get X = 800 students. The answer is 800.
Question: A pen costs $9 more than a pencil. If a pencil costs $2, find the total cost of both items.
Answer: A pen costs $9 more than $2 which is $9 + $2 = $11. Altogether they cost $11 + $2 = $13. The answer is 13.
[Question]Stacy, Steve and Sylar have 1100 berries total. Stacy has 4 times as many berries as Steve, and Steve has double the number of berries that Skylar has. How many berries does Stacy have?
[Answer]Let x be the number of berries Skylar has. Steve has 2x berries. Stacy has 4(2x) = 8x berries. 1100 = x + 2x + 8x. 1100 = 11x. x = 100 berries. Stacy has 8(100) = 800 berries. The answer is 800.
Q: Louise is in a toy store. She already has 28 toys worth $10 each in her cart. On her way to the till she adds 20 teddy bears to the cart. If the $580 in Louise’s wallet is exactly enough to pay for all the toys, how much does each teddy bear cost?
A: Initially, Louise's cart has toys worth 10 * 28 = 280 dollars. If Louise pays for the toys originally in her cart, her wallet will remain with 580 - 280 = 300 dollars. Dividing the remaining amount by the number of teddy bears gives 300 / 20 = 15 dollars. The answer is 15.
Question: Alec is running for Class President. He thinks that if he can get three-quarters of the class to vote for him then there is no chance anyone else can beat him. Half of the class have already said they will vote for him but out of the remaining students, only 5 have said they are thinking about voting for him. He surveys the students who are thinking about voting for someone else, and changes his flyers to reflect the issues these students are concerned about. This results in a fifth of these students saying they'll vote for him. If Alec's class has 60 students and everyone who said they will vote for him does so, how many more votes does Alec need to reach his goal number of votes?
Answer:

assistant: To calculate Alec's goal number of votes, we need to know that 60 students / 4 = 15 students is equal to one - quarter of the class students. Alec's goal is therefore 15 students * 3 quarters = 45 votes. Half of the class said they will vote for him, so there are already 60 students / 2 = 30 votes. Another 5 students are thinking about voting for him which leaves a total so far of 30 + 5 = 35 votes. This means there are 60 students - 35 voting for Alec = 25 students not voting for Alec. A fifth of these decided to vote, so this is a further 25 students / 5 = 5 votes. Alec is therefore receiving a total of 35 + 5 = 40 votes. So he has missed his goal by 45 goal votes - 40 actual votes = 5 votes. The answer is 5.