He covers 4km / hr * 4hrs = 16km in the first 4 hours. He has 24 - 16 = 8km left to cover. He has 8 - 4 = 4 hours to cover the remaining 8km. He has to travel at a speed of 8km / 4hrs = 2km / hr to be right on time.
The answer: 2
Reverse engineering the question: A man intends to complete a journey of 24 km in 8 hours. If he travels at a speed of 4km/hr for the first four hours, at what speed does he need to travel for the remainder of the journey to be right on time?


Reasoning and answer: If the shadows lengthen by 5 feet per hour, this means that in 6 hours the shadows would have lengthened from zero to 5 * 6 = 30 feet. Since there are 12 inches in every foot, this means the building's shadow would be 30 * 12 = 360 inches in length.
The answer: 360
What was the question?
Question: Every hour past noon shadows from a building stretch an extra 5 feet, starting at zero at noon. How long are the shadows from the building 6 hours past noon in inches?


The total number of teachers who ate pizza is 2 / 3 * 30 = 20. 30 - 20 = 10 teachers did not eat pizza. The number of staff members who ate pizza is 4 / 5 * 45 = 36. The number of staff members who did not eat pizza is 45 - 36 = 9. The number of non - pizza eaters is 9 + 10 = 19.
The answer: 19
Reverse engineering the question: At Esme's school, there are 30 teachers and 45 staff members. On a Monday morning, The Best Pizza Inn brought pizza for the staff and teachers as a promotion offer. If 2/3 of the teachers and 4/5 of the staff members ate Pizza, how many non-pizza eaters are at Esme's school?


Reasoning and answer: If Pete walks on hands at 1 / 4 what Tracy can do 1 - handed cartwheels, then Tracy can do 1 - handed cartwheels at 2 * 4 = 8 miles per hour. Since Tracy does 1 - handed cartwheels twice the rate of Susan's forward walking, then Susan walks at 8 / 2 = 4 miles per hour. Pete walks backwards 3x faster than Susan walks forward, and thus Pete walks backwards at 4 * 3 = 12 miles per hour.
The answer: 12
What was the question?
Question: Pete walks backwards three times faster than Susan walks forwards, and Tracy does one-handed cartwheels twice as fast as Susan walks forwards. But Pete can walk on his hands only one quarter the speed that Tracy can do cartwheels. If Pete walks on his hands at 2 miles per hour, how fast can Pete walk backwards, in miles per hour?


First find how many minutes Jenna tans each of the first two weeks: 30 minutes / day * 2 days / week = 60 minutes / week. Then multiply that number by the number of weeks to find how many minutes Jenna tans in the first half of the month: 60 minutes / week * 2 weeks = 120 minutes. Then subtract that time from the total time Jenna can spend tanning to find how many more minutes she can tan: 200 minutes - 120 minutes = 80 minutes.
The answer: 80
Reverse engineering the question: Jenna's doctor tells her that she should tan no more than 200 minutes a month. If she tans 30 minutes a day, two days a week for the first two weeks of the month, how many minutes can she tan in the last two weeks of the month?


She had 5 + 8 = 13 crayons to start with. She gave out 3 + 1 = 4 crayons to Becky. She will have 13 - 4 = 9 crayons left.
The answer: 9
Reverse engineering the question:
Mary has 5 green crayons and 8 blue crayons of different shades. If she gives out 3 green crayons and 1 blue crayon to Becky, how many crayons does she have left?