Question: Eric sorted 150 colored pencils into 5 containers for his art class. Before class, another teacher brought him 30 more pencils. How many can he evenly distribute between the five containers now?
Answer with step-by-step thinking: Before the extra colored pencils, he had 150 / 5 = 30 colored pencils in each container. With the other colored pencils, he is given he now has 150 + 30 = 180 colored pencils. If you distribute them evenly each container should have 180 / 5 = 36 colored pencils.
So the answer is 36.

Question: Tracy set up a booth at an art fair. 20 people came to look at her art. Four of those customers bought two paintings each. The next 12 of those customers bought one painting each. The last 4 customers bought four paintings each. How many paintings did Tracy sell at the art fair?
Answer with step-by-step thinking: The first 4 customers bought 4 * 2 = 8 paintings. The next 12 customers bought 12 * 1 = 12 paintings. The last 4 customers bought 4 * 4 = 16 paintings. In total Tracy sold 8 + 12 + 16 = 36 paintings.
So the answer is 36.

Question: A swimming pool is being emptied through a drain at the bottom of the pool and filled by a hose at the top. The drain can empty the pool in 4 hours and the hose can fill the pool in 6 hours. The pool holds 120 liters of water. If the pool starts filled with water, how much water will be left after 3 hours?
Answer with step-by-step thinking:
It takes the drain 4 hours to empty the pool, so it drains at a rate of 120 liters / 4 hours = 30 liters / hour. After 3 hours, the drain will have removed 3 * 30 = 90 liters of water from the pool. It takes the hose 6 hours to fill the pool, so it fills at a rate of 120 liters / 6 hours = 20 liters / hour. After 3 hours, the hose will have added 3 * 20 = 60 liters of water to the pool. After 3 hours, there will be 120 liters + 60 liters 90 liters = 90 liters of water left in the pool.
So the answer is 90.