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? Give the rationale and then the answer.
Let's think step by step. 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.

It takes 15 mink skins to make a coat. Andy buys 30 minks and each mink has 6 babies, but half the total minks are set free by activists. How many coats can he make? Give the rationale and then the answer.
Let's think step by step. First find the total number of baby minks: 30 minks * 6 babies / mink = 180 minks. Add this to the number of adult minks: 180 minks + 30 minks = 210 minks. Then divide this number in half to find how many aren't set free: 210 minks / 2 = 105 minks. Then divide the remaining number of minks by the number of minks per coat to find the number of coats: 105 minks / 15 minks / coat = 7 coats.. The answer is: 7.

Robbie weighs 100 pounds. Patty was 4.5 times as heavy as Robbie, but she has since lost 235 pounds by working out. How many more pounds does Patty weigh than Robbie now? Give the rationale and then the answer.
Let's think step by step. Patty used to weigh 100 * 4.5 = 450 pounds. Patty weighs 450 - 235 = 215 pounds after working out. Patty weighs 215 - 100 = 115 more pounds than Robbie.. The answer is: 115.