In the first set there are 5 broken marbles because 50 x .1 = 5. In the second set there are 12 broken marbles because 60 x .2 = 12. There are 17 broken marbles in total because 5 + 12 = 17.
The answer: 17
Reverse engineering the question: Gabriel is looking at her marble sets. She sees that in the first set 10% of her marbles are broken. In the second set, 20% of the marbles are broken. The first set contains 50 marbles. The second set contains 60. How many marbles are broken in total?


Reasoning and answer: The zebra sleeps for 4 + 2 = 6 hours. During one week, the cougar sleeps 4 * 7 = 28 hours. And the zebra sleeps 6 * 7 = 42 hours. Both animals sleep for 28 + 42 = 70 hours during one week.
The answer: 70
What was the question?
Question: A cougar is sleeping for 4 hours at night, and a zebra for 2 hours more. How much time do both animals sleep in one week?


If Jared counted 300 cars, and Ann counted 15% more, then Ann counted 1.15 * 300 = 345 cars. If Ann counted 7 cars more than their friend Alfred, then Alfred counted 345 - 7 = 338 cars. The total number of cars counted by all of them will be 338 + 345 + 300 = 983 cars.
The answer: 983
Reverse engineering the question: Jared counted 15% fewer cars than his sister Ann while they were watching the road from the school, and Ann counted 7 more cars than their friend Alfred. If Jared counted 300 cars, how many cars did all of them count?


Reasoning and answer: The increase is $100 x 10 / 100 = $10. So you have to give $100 + $10 = $110 to your friend today.
The answer: 110
What was the question?
Question: Last month, you borrowed $100 from your friend. If you promise to pay her today, how much will you give to your friend if both of you agreed to return the money with a 10% increase?


The truck driver can go 3 * 12 = 36 miles on the gas in his tank. He needs to go 90 - 36 = 54 more miles. Thus, the truck driver needs to put 54 / 3 = 18 more gallons of gas in his semi.
The answer: 18
Reverse engineering the question: A truck driver’s heavy semi truck can go 3 miles per gallon of gas. The truck driver needs to put gas in his truck at one gas station, but wants to put the minimum amount he needs to get him to a much cheaper gas station 90 miles away. He already has 12 gallons of gas in his tank. How many more gallons does the truck driver need to put in his semi to make it to the cheaper gas station?


His total expenditure so far is $50 + $35 + $15 = $100. To make a profit of 10%, he has to make a total of $100 + ($100 * (10 / 100) = $110 from sales. To make $110 from the sales of 10 bags, each bag should cost $110 / 10 = $11.
The answer: 11
Reverse engineering the question:
While cultivating a small farm, a farmer spent $50 on corn seeds, $35 on fertilizers and pesticides, and $15 on labor. After a successful harvest, he was able to gather 10 bags of corn. How much should he sell each bag, if he wants to make a profit of 10%?