Grayson has 100 questions on a test. He answers some of the questions for 2 hours, taking two minutes for each answer, then realizes he doesn't know the rest of the questions. How many questions does Grayson leave unanswered when he submits his test? Give the rationale and then the answer.
Let's think step by step. Each hour contains 60 minutes, so after 2 hours he took 2 * 60 = 120 minutes. If each question takes two minutes, then he answered 120 / 2 = 60 questions. Unanswered questions is 100 - 60 = 40 questions.. The answer is: 40.

If 2 machines in a factory make 10 cell phones each minute, how many machines would it take to make 50 cell phones a minute? Give the rationale and then the answer.
Let's think step by step. First, we need to determine how many cell phones each machine makes per minute. We do this by performing 10 / 2 = 5 cell phones each minute per machine. Next, we determine how many machines are needed in total by dividing the desired outcome of 50 by the rate of production of an individual machine, finding 50 / 5 = 10 machines needed.. The answer is: 10.

There are one hundred tickets to be sold for a volleyball game. Andrea sold twice as many tickets as Jude while Sandra sold 4 more than half the number of tickets Jude sold. If Jude sold 16 tickets, how many tickets need to be sold? Give the rationale and then the answer.
Let's think step by step. Andrea sold 16 x 2 = 32 tickets. Half the number of tickets Jude sold is 16 / 2 = 8. So, Sandra sold 8 + 4 = 12 tickets. Thus, Andrea, Jude, and Sandra sold a total of 32 + 16 + 12 = 60 tickets. Therefore, 100 - 60 = 40 tickets need to be sold.. The answer is: 40.