Question: Michael wants to dig a hole 400 feet less deep than twice the depth of the hole that his father dug. The father dug a hole at a rate of 4 feet per hour. If the father took 400 hours to dig his hole, how many hours will it take for Michael to dig a hole that is 400 feet less than twice as deep as his father's hole working at the same rate? Think carefully first, then make a decision:
Since the father dug a hole with a rate of 4 feet per hour, if the father took 400 hours digging the hole, he dug a hole 4 * 400 = 1600 feet deep. Twice the depth of the hole that Michael's father dug is 2 * 1600 = 3200 feet. Michael wants to dig a hole 400 feet less than twice the depth of the hole that his father dug, meaning he wants to dig a hole 3200 - 400 = 2800 feet deep. To dig a hole that is 400 feet less than twice as deep as his father's hole working at a rate of 4 feet per hour, Michael will have to work for 2800 / 4 = 700 hours. So the answer is 700.