Come up with a question and reasoning that would justify [10] as the answer.
The question is: Donna is catering for a party. She makes 20 sandwiches and then cuts them in half, before cutting them in half again. She then gives everyone 8 portions. How many people can she feed?
Reasoning: First, we need to determine the overall number of portions. To do this, we begin by performing 20 * 2 = 40 portions after the first halving. Next, we take this portion number and double it again, performing 40 * 2 = 80 portions after the second halving. Lastly, we divide this portion number by the number of portions each person will be served, performing 80 / 8 = 10 people served.

Come up with a question and reasoning that would justify [480] as the answer.
The question is: The number of math problems that Marvin practiced today is three times as many as the number of problems he solved yesterday. His friend, Arvin, has practiced twice as many math problems on each day. How many math problems have they practiced altogether if Marvin solved 40 math problems yesterday?
Reasoning: If Marvin solved 40 math problems yesterday, he has solved 40 * 3 = 120 math problems today. The total number of math problems that Marvin has practiced is 120 + 40 = 160. Arvin has practiced twice as many as Marvin, so has practiced 160 * 2 = 320 problems. Together, Marvin and Arvin have solved 320 + 160 = 480 math problems.

Come up with a question and reasoning that would justify [50] as the answer.
The question is: John buys 10 packs of magic cards. Each pack has 20 cards and 1/4 of those cards are uncommon. How many uncommon cards did he get?
Reasoning: Each pack has 20 / 4 = 5 uncommons. So he got 10 * 5 = 50 uncommons.