Mel is three years younger than Katherine. When Katherine is two dozen years old, how old will Mel be in years? Give the rationale and then the answer.
Let's think step by step. When Katherine is 2 dozen years old, she will be 2 * 12 = 24 years old. If Mel is three years younger than Katherine, then when Katherine is 24 years old, Mel will be 24 - 3 = 21 years old.. The answer is: 21.

Padma is trading cards with Robert. Padma started with 75 cards and traded 2 or her valuable ones for 10 of Robert's cards. Robert started with 88 of his own cards and traded another 8 of his cards for 15 of Padma's cards. How many cards were traded between both Padma and Robert? Give the rationale and then the answer.
Let's think step by step. Padma traded 2 + 15 of her cards = 17 cards. Robert traded 10 + 8 of his cards = 18 cards. In total, between both of them Padma and Robert traded 17 + 18 = 35 cards.. The answer is: 35.

Jerry takes 2 antacids that weigh 2 grams each and are 5% zinc by weight. Then he takes three more smaller antacids that weigh 1 gram each and have 15% zinc. How many milligrams of zinc does he eat? Give the rationale and then the answer.
Let's think step by step. First find the total weight of the big antacids: 2 grams / antacid * 2 antacids = 4 grams. Then convert that weight to milligrams: 4 grams * 1000 mg / gram = 4000 mg. Then multiply that number by 5% to find how much zinc is in the big antacids: 4000 mg * 5% = 200 mg. Then find the total weight of the smaller antacids in milligrams: 3 antacids * 1 gram / antacid * 1000 mg / gram = 3000 mg. Then multiply that number by the percent of zinc to find the amount of zinc in the small antacids: 3000 mg * 15% = 450 mg. Then add the zinc Jerry gets from each set of pills to find the total amount of zinc he eats: 450 mg + 200 mg = 650 mg.. The answer is: 650.