Johann and two friends are to deliver 180 pieces of certified mail. His friends each deliver 41 pieces of mail. How many pieces of mail does Johann need to deliver? Give the rationale and then the answer.
Let's think step by step. Friends = 41 * 2 = 82. Johann = 180 - 82 = 98. Johann must deliver 98 pieces of mail.. The answer is: 98.

Angie bought 3 lbs. of coffee at the store today. Each lb. of coffee will brew about 40 cups of coffee. Angie drinks 3 cups of coffee every day. How many days will this coffee last her? Give the rationale and then the answer.
Let's think step by step. A pound of coffee makes 40 cups of coffee, so 3 lbs. coffee * 40 cups of coffee per lb. = 120 cups of coffee. Angie drinks 3 cups of coffee a day, so she has enough coffee to last her 120 cups of coffee / 3 cups of coffee per day = 40 days.. The answer is: 40.

Rory collects rainwater. He has 100 L of rainwater in his tank. During a heavy rainstorm, water flows into the tank at a rate of 2 L/min for 90 minutes. How much water is in the tank at the end of the heavy rain? Give the rationale and then the answer.
Let's think step by step. During the heavy rain, the tank collects 2 * 90 = 180 L of water. The tank has a total of 100 + 180 = 280 L of water.. The answer is: 280.