Question: John is 10 years old. His sister is twice his age. When he is 50 years old, how old will his sister be?
Answer: His sister is 10 * 2 = 20 years old. Their age difference is 20 - 10 = 10 years. Therefore when he is 50 she will be 50 + 10 = 60 years old. The answer is 60.
[Question]In a jar that has 50 ants, the number of ants in the jar doubles each hour. How many ants will be in the jar after 5 hours?
[Answer]After first hour, 50 * 2 = 100 ants. After the second hour, 100 * 2 = 200 ants. After the third hour, 200 * 2 = 400 ants. After the fourth hour, 400 * 2 = 800 ants. After the fifth hour, 800 * 2 = 1600 ants. The answer is 1600.
Q: After working out for 3 hours, three friends go out for lunch. Adam spends two-thirds as much money on lunch as Rick. Rick and Jose eat lunch of the same price. If Jose ate lunch worth $45, what is the cost of lunch for all three?
A: Since Rick and Jose's lunch cost was the same, Adam spent 2 / 3 * 45 = $30 on his lunch. The three friends ate food worth 30 + 45 + 45 = $120. The answer is 120.
Question: While Paul watches movies, he runs on his treadmill. He can run a mile in 12 minutes. He watches two movies, which are an average length of 1.5 hours. How many miles does he run?
Answer: He runs for 3 hours because 2 x 1.5 = 3. He runs for 180 minutes because 3 x 60 = 180. He runs 15 miles because 180 / 12 = 15. The answer is 15.
[Question]Marcos has to get across a 5 mile lake in his speedboat in 10 minutes so he can make it to work on time. How fast does he need to go in miles per hour to make it?
[Answer]10 minutes for 5 miles means 10 minutes / 5 miles = 2 minutes / mile. 1 hour is 60 minutes so 60 minutes / hour / 2 minutes / mile = 30 miles / hour. The answer is 30.
[Question]Isaac cut his 30 meters ribbon into 6 equal parts. He then used 4 parts of the ribbon. How many meters of ribbon are not used?
[Answer]
Each part is 30 / 6 = 5 meters long. Since Liam used 4 parts, then he used 5 x 4 = 20 meters of the ribbon. So, 30 - 20 = 10 meters of ribbon is not used. The answer is 10.