If there were 500 visitors, and 40% of them fell ill, the number of visitors who fell ill is 40 / 100 * 500 = 200 people. The number of visitors who did not get ill is 500 - 200 = 300.
The answer: 300
Reverse engineering the question: After a visit to the newly opened aquarium, 40 percent of the aquarium visitors fell ill from a mysterious disease. If there were 500 visitors, how many of them did not fall ill?


Reasoning and answer: He saves 150,000 * .1 = $15,000 per year. He needs 450,000 * .2 = $90,000. So he needs to save for 90,000 / 15,000 = 6 years.
The answer: 6
What was the question?
Question: Mike is saving up to buy a house. He puts away 10% of his $150,000 a year salary. He needs to save up 20% of the cost of a $450,000 house for a downpayment. How long will it take?


Mark's team scores 25 2 pointers, meaning they scored 25 * 2 = 50 points in 2 pointers. His team also scores 6 3 pointers, meaning they scored 8 * 3 = 24 points in 3 pointers. They scored 10 free throws, and free throws count as one point so they scored 10 * 1 = 10 points in free throws. All together his team scored 50 + 24 + 10 = 84 points. Mark's opponents scored double his team's number of 2 pointers, meaning they scored 50 * 2 = 100 points in 2 pointers. His opponents scored half his team's number of 3 pointers, meaning they scored 24 / 2 = 12 points in 3 pointers. They also scored half Mark's team's points in free throws, meaning they scored 10 / 2 = 5 points in free throws. All together Mark's opponents scored 100 + 12 + 5 = 117 points. The total score for the game is both team's scores added together, so it is 84 + 117 = 201 points.
The answer: 201
Reverse engineering the question: Mark's basketball team scores 25 2 pointers, 8 3 pointers and 10 free throws. Their opponents score double the 2 pointers but half the 3 pointers and free throws. What's the total number of points scored by both teams added together?


Reasoning and answer: There were 3 x 8 = 24 slices of pizza. Since there were 6 persons, then each person ate 24 / 6 = 4 slices.
The answer: 4
What was the question?
Question: John with his five friends ordered 3 pizzas. Each pizza had 8 slices. If they all finished and ate the same amount of pizzas, how many slices did each person eat?


The guests ate 28 / 4 = 7 cucumber sandwiches. The guests ate 12 / 2 = 6 egg sandwiches. They ate a total of 7 + 6 = 13 sandwiches. They ate a total of 13 x 2 = 26 slices of bread.
The answer: 26
Reverse engineering the question: Kiki made 10 cucumber sandwiches and 8 egg sandwiches for the tea party. Each cucumber sandwich was cut into 4 triangles. Each egg sandwich was cut into 2 rectangles. If her guests ate 28 triangles and 12 rectangles, how many slices of bread did they eat?


Martin invited 5 * 2 = 10 people from his school. People from the sports club got 5 + 10 = 15 invitations. So in total from the sports club, hometown and school, Martin invited 5 + 10 + 15 = 30 people. All other invitations are 20% of the previous total, which means 20 / 100 * 30 = 6. That means Martin invited to his party 30 + 6 = 36 people.
The answer: 36
Reverse engineering the question:
Martin is organizing a party, and he invited many of his colleagues. He invited 5 people from his hometown and twice as many people from his school. Martin invited also as many people from his sports club as the sum of people invited from his hometown and his school. The remaining invitations represent 20% of the total previously mentioned. How many people can potentially come to the party Martin is organizing?