Question: John is half times younger than his father, who is 4 years older than John's mother. If John's father is 40 years old, what's the age difference between John and his mother?
Answer: John is half times his father's age. Thus 1 / 2 * 40 = 20 years. Since the mother is 4 years younger than the father, she is 40 - 4 = 36 years old. The age difference between John and his mother is 36 - 20 = 16 years. The answer is 16.

Question: Andy started out the year weighing 156 pounds. He then grew 3 inches and gained 36 pounds. Andy wasn't happy with his weight and decided to exercise. Over the next 3 months, he lost an eighth of his weight every month. How much less does Andy weigh now than at the beginning of the year?
Answer: Andy weighed 156 + 36 = 192 pounds after growing taller. An eighth of his weight is 1 / 8 x 192 = 24 pounds. Over the next 3 months, Andy lost 24 x 3 = 72 pounds. He now weighs 192 - 72 = 120 pounds. Andy weighs 156 - 120 = 36 pounds less than at the beginning of the year. The answer is 36.

Question: John climbs 3 staircases. The first staircase has 20 steps. The next has twice as many steps as the first. The final staircase has 10 fewer steps than the second one. Each step is 0.5 feet. How many feet did he climb?
Answer: The second flight had 20 * 2 = 40 steps. The third had 40 - 10 = 30 steps. So in total, he climbed 20 + 40 + 30 = 90 steps. So he climbed 90 * .5 = 45 feet. The answer is 45.

Question: Lucy lost one-third of her money. She then spent one-fourth of the remainder, and only left with $15. How much money did Lucy have at the beginning?
Answer:
The $15 is 1 - 1 / 4 = 3 / 4 of the money left. Since 3 / 4 is equal to $15, then 1 / 4 is equal to $15 / 3 = $5. So Lucy had $5 x 4 = $20 left after losing 1 / 3 of her money. Hence, $20 is 1 - 1 / 3 = 2 / 3 of the money that Lucy had at the beginning. Since 2 / 3 is equal to $20, then 1 / 3 is equal to $20 / 2 = $10. Therefore, Lucy had $10 x 3 = $30 at the beginning. The answer is 30.