The total number of pages in the series is 14 books * 200 pages / book = 2800 pages. Sabrina read 4 books * 200 pages / book = 800 pages in the first month. She still has 14 books - 4 books = 10 books after reading four books. In the second month, she read 1 / 2 * 10 books = 5 books. The total number of pages she read is 5 books * 200 pages / book = 1000 in the second month. In total, Sabrina 1000 pages + 800 pages = 1800 pages in two months. Sabrina has to read 2800 pages - 1800 pages = 1000 more pages to complete the total series.
The answer: 1000
Reverse engineering the question: Sabrina went to the library and found a historical series novel called The Rangers Apprentice. There are 14 books in the series, and each book has 200 pages. She read four books in a month and half the number of books remaining in the second month. What's the total number of pages Sabrina has to read to finish the whole series?
Reasoning and answer: Last week, she used 15 gallons * 0.2 = 3 gallons less fuel than she used this week. This means that she used 15 gallons 3 gallons = 12 gallons of fuel last week. In total, Mary used 15 gallons + 12 gallons = 27 gallons of fuel.
The answer: 27
What was the question?
Question: Mary used 15 gallons of fuel this week. Last week she used 20% less. How much fuel did she use in total for the two weeks?
The gum cost $1.5 / 2 = $.75 per pack. So he pays $.75 * 2 = $1.5 for the gum. He pays $1.5 * 3 = $4.5 for the candy bars. So in total, he pays $1.5 + $4.5 = $6.
The answer: 6
Reverse engineering the question: John buys 2 packs of gum and 3 candy bars. Each stick of gum cost half as much as the candy bar. If the candy bar cost $1.5 each, how much did he pay in total?
Reasoning and answer: James is 35 - 23 = 12 years younger than John. 5 years less than Tim's age is 79 - 5 = 74 years old. So John is 74 / 2 = 37 years old. That means James is 37 - 12 = 25 years old.
The answer: 25
What was the question?
Question: James turned 23 the same time John turned 35. Tim is 5 years less than twice John's age. If Tim is 79 how old is James?
Let B be the number of apples that Buffy stole. Then 79 - B - 26 = 8. Combining constants produces 53 - B = 8. Adding B to both sides produces 52 = B + 8. Thus the number of apples stolen by Buffy is B = 53 - 8 = 45.
The answer: 45
Reverse engineering the question: Every morning, Carla puts 79 apples in her backpack to eat for lunch. Unfortunately, Buffy stole some of Carla's apples on the school bus, and 26 apples fell out of a hole on the bottom. So at lunchtime, Carla only had 8 apples remaining. How many apples did Buffy steal from Carla?
If Selma has fifty marbles, then Merill and Elliot together have 50 - 5 = 45 marbles. We'll assume the number of marbles that Elliot has is x. If Merill has twice as many marbles as Elliot, then the total number of marbles that Merill and Elliot have together is 2x + x = 45 marbles. This translates to 3x = 45. The number of marbles that Elliot has is x = 45 / 3. This means Elliot has x = 15 marbles. Since Merill has twice as many marbles as Elliot, Merill has 2 * 15 = 30 marbles.
The answer: 30
Reverse engineering the question:
Merill has twice as many marbles as Elliot and the two of them together have five fewer marbles than Selma. If Selma has fifty marbles, how many marbles does Merill have?