John climbs up 9 flights of stairs. Each flight is 10 feet. If each step is 18 inches, how many steps does he climb up? Give the rationale and then the answer.
Let's think step by step. He has to climb 9 * 10 = 90 feet. That means he needs to climb 90 * 12 = 1080 inches. That means he needs to climb 1080 / 18 = 60 stairs.. The answer is: 60.

When Doctor Lindsay works in her office, she usually sees 4 adult patients and 3 child patients every hour. If the cost for an adult's office visit is $50, and the cost for a child's office visit is $25, how much money, in dollars, does Doctor Lyndsay receive in a typical 8-hour day for seeing all her patients? Give the rationale and then the answer.
Let's think step by step. For 4 adult patients per hour, Dr. Lindsay receives 4 * 50 = 200 dollars per hour. For the 3 child patients per hour, Dr. Lindsay receives 3 * 25 = 75 dollars per hour. Thus, Dr. Lindsay receives 200 + 75 = 275 dollars per hour. In an 8 - hour day, Dr. Lindsay receives 8 * 275 = 2200 dollars.. The answer is: 2200.

John is a door-to-door salesman. He visits 50 houses a day. 20% of them buy something from them. Of those that buy something half buy a $50 set of knives and the other half buy a $150 set of knives. How much does he sell a week when he works 5 days a week? Give the rationale and then the answer.
Let's think step by step. There are 50 * .2 = 10 houses buying from him per day. Of those 10 / 2 = 5 buy each type of knife set. So he gets 5 * 50 = $250 per day from the cheap set. He also gets 5 * 150 = $750 from the expensive set. So he makes a total of 250 + 750 = $1000 per day. That means he makes 1000 * 5 = $5000.. The answer is: 5000.