Question: Jeannie hikes the 12 miles to Mount Overlook at a pace of 4 miles per hour, and then returns at a pace of 6 miles per hour. How long did her hike take, in hours?
Answer: Up, took 12 / 4 = 3 hours. Down, took 12 / 6 = 2 hours. Total time was 3 + 2 = 5 hours. The answer is 5.

Question: John plays a game for 4 hours a day every day for 2 weeks. After all that time, he is only 40% done. He increased his playtime to 7 hours a day. How long until he finishes the game?
Answer: There are 7 * 2 = 14 days in two weeks. So he played 14 * 4 = 56 hours. That means the total length of the game is 56 / .4 = 140 hours. So he has 140 - 56 = 84 hours to beat the game. So it will take him 84 / 7 = 12 days to beat the game. The answer is 12.

Question: Five years ago, the sum of Sebastian's age and his sister's age was 3/4 of their father's age. How old is their father today if Sebastian is 40 years old and 10 years older than his sister?
Answer: If Sebastian is 40 years old and 10 years older than his sister, his sister is 40 - 10 = 30 years old. Five years ago, Sebastian was 40 - 5 = 35 years old. Similarly, Sebastian's sister's age was 30 - 5 = 25 years old. The sum of their ages five years ago was 25 + 35 = 60. Five years ago, the sum of Sebastian's age and his sister's age was 3 / 4 of their father's age, meaning their father's age was 60 / 3 / 4 = 80 years. The father's age is now 80 + 5 = 85. The answer is 85.

Question: Mike bought a DVD of his favorite movie. He paid $5 for it at the store. A friend of Mike's, Steve, saw this and also decided to buy a DVD of the movie, but it was already sold out. He needed to order it online, which cost him twice as much. And in addition, he needed to pay the shipping costs which were 80% of the price of the film he ordered. How much did Steve pay to get the DVD in total?
Answer:
The cost of the movie online was twice what Mike paid, so 2 * 5 = $10. The shopping costs were standing at 80 / 100 * 10 = $8. So in total Steve paid 10 + 8 = $18. The answer is 18.