Come up with a question and reasoning that would justify [874] as the answer.
The question is: Lara is a contestant on a fun game show where she needs to navigate an inflated bouncy house obstacle course. First she needs to carry a backpack full of treasure through the obstacle course and set it down on the other side, which she does in 7 minutes and 23 seconds. Second, she needs to crank open the door to the obstacle course so she can go back through, which takes her 73 seconds. After she gets through the door she traverses the obstacle course again and makes it out faster without the backpack, in 5 minutes and 58 seconds. How many seconds total does it take her to complete the obstacle course?
Reasoning: It takes Lara 7 minutes and 23 seconds to make it through the obstacle course the first time. 7 minutes x 60 seconds per minute = 420 seconds + 23 seconds = 443 seconds to get through the first part of the obstacle course. The second stage of the obstacle course she completes in 73 seconds + 443 seconds = 516 seconds. It takes 5 minutes and 58 seconds for Lara to get through the obstacle course the second time. 5 minutes x 60 seconds per minute = 300 + 58 seconds = 358 seconds. Combined, it takes Lara 516 + 358 seconds = 874 seconds for Lara to run the whole obstacle course.

Come up with a question and reasoning that would justify [15] as the answer.
The question is: Karen is planning writing assignments for her fifth grade class. She knows each short-answer question takes 3 minutes to answer, each paragraph takes 15 minutes to write, and each essay takes an hour to write. If Karen assigns 2 essays and 5 paragraphs, how many short-answer questions should she assign if she wants to assign 4 hours of homework total?
Reasoning: First figure out how many minutes 4 hours is: 4 hours * 60 minutes / hour = 240 minutes. Then figure out how long the two essays will take by multiplying the time per essay by the number of essays: 2 essays * 1 hour / essay * 60 minutes / hour = 120 minutes. Use the same method to find the total time spent writing paragraphs: 15 minutes / paragraph * 5 paragraphs = 75 minutes. Now subtract the time spent on essays and paragraphs from the total time to find the time spent on all the short answer questions: 240 minutes - 120 minutes - 75 minutes = 45 minutes. Finally, divide the total time spent on short - answer questions by the time per question to find the number of questions: 45 minutes / 3 minutes / question = 15 questions.

Come up with a question and reasoning that would justify [21] as the answer.
The question is: Valerie needs to put stamps on the envelopes she is about to mail. She has thank you cards for each of her grandmother, uncle and aunt for the birthday presents they sent. She also has to pay the water bill and the electric bill separately. She wants to send three more mail-in rebates than she does bills and she has twice as many job applications as rebates to mail. How many stamps does she need if everything needs 1 stamp except the electric bill, which needs 2?
Reasoning: Valerie has to send a thank you card to each of 3 people, so she has 3 * 1 = 3 thank you cards to mail. She has 2 bills to mail. She has 3 more rebates than bills, so 3 + 2 = 5 mail - in rebates to mail. She has twice as many job applications as rebates, so she has 2 * 5 = 10 applications to mail. She has 3 + 2 + 5 + 10 = 20 pieces of mail to send. The electric bill needs an extra stamp, so she needs 20 + 1 = 21 stamps.