Q: Harry is a professional dog-walker. He is paid to go on long walks with dogs while their families are away from home. On Monday, Wednesday, and Friday, Harry walks 7 dogs. On Tuesday, he walks 12 dogs. And on Thursday he walks 9 dogs. He is paid $5 for each dog that he walks. How many dollars does Harry earn in a week?
A: Monday, Wednesday, and Friday, Harry walks a total of 3 * 7 = 21 dogs. Thus, in a week he walks 21 + 12 + 9 = 42 dogs. At a rate of $5 per dog, Harry ears $5 * 42 = $210 per week. The answer is 210.

Q: Lilith originally had five dozen water bottles that she needed to sell at $2 each to get exactly enough money to buy her friend a birthday gift. However, at the store, Lilith realized she could not sell at $2 because the regular price was $1.85 per water bottle in her town, and she had to reduce her price to $1.85 as well to sell her water bottles. Calculate the total amount of money Lilith will have to find to buy her friend the birthday gift after selling her water bottles at the reduced cost.
A: Lilith had 5 dozen water bottles, and since a dozen has 12 water bottles, the total number of water bottles she had was 12 bottles / dozen * 5 dozen = 60 bottles. To buy her friend the birthday gift, Lilith originally had to sell her water bottles for a total of 60 bottles * $2 / bottle = $120. When she reduced the price to $1.85 to meet the regular price, the total amount of money she had from the sales was $1.85 / bottle * 60 bottles = $111. To buy her friend the birthday gift, Lilith has to find $120 - $111 = $9 more. The answer is 9.

Q: Sabrina gave 10 cookies to her brother. Her mother gave Sabrina half the number of cookies she gave her brother. Then Sabrina gave two-thirds of her cookies to her sister. If Sabrina had 20 cookies at the start, how many cookies are left with her?
A:
Sabrina had 20 - 10 = 10 cookies left after giving 10 cookies to her brother. Sabrina's mother gave her 10 / 2 = 5 cookies. So, she had 10 + 5 = 15 cookies then. She gave 15 x 2 / 3 = 10 cookies to her sister. Therefore, she only has 15 - 10 = 5 cookies left. The answer is 5.