Q: Johnny has been playing guitar for a while now. He practices the same amount each day. As of 20 days ago he had half as much practice as he has currently. How many days will pass before Johnny has 3 times as much practice as he does currently?
A: 80
Step-by-step reasoning process: If Johnny had half as much practice as he currently has as of 20 days ago, this means he has 20 * 2 = 40 days worth of practice currently. Therefore, to have three times as much practice as he currently has, he'd need to practice for 40 * 3 = 120 days. Since he's already practiced for 40 days, this means he needs to practice or 120 - 40 = 80 more days.

Q: Santana has 7 brothers. 3 of them have birthdays in March, 1 of them has a birthday in October, 1 has a birthday in November, and another 2 of them were born in December. If Santana always buys each of her brothers a birthday present and a Christmas present, how many more presents does she have to buy in the second half of the year than the first half of the year?
A: 8
Step-by-step reasoning process: Santana has 1 + 1 + 2 = 4 brothers with birthdays in the second half of the year. She has 7 brothers - 4 brothers = 3 brothers with birthdays in the first half of the year. Altogether, she has to buy 4 + 7 = 11 presents in the second half of the year. Therefore, she has to buy 11 - 3 = 8 more presents in the second half of the year.

Q: In preparation for his mountain climbing, Arvin wants to run a total of 20 kilometers in a week. On the first day, he ran 2 kilometers. On each subsequent day, he increased his running distance by 1 kilometer over the previous day. If he runs for 5 days a week, how many kilometers did he run on the 5th day?
A: 6
Step-by-step reasoning process: On the second day, Arvin ran 2 + 1 = 3 kilometers. On the third day, he ran 3 + 1 = 4 kilometers. On the fourth day, he ran 4 + 1 = 5 kilometers. So on the fifth day, he ran 5 + 1 = 6 kilometers.

Q: Every day, Sara bakes 10 cakes and puts them in his refrigerator. He does this for 5 days. Carol then comes over and eats 12 of his cakes. If it takes 2 cans of frosting to frost a single cake, how many cans of frosting does Bob need to frost the remaining cakes?
A: 76
Step-by-step reasoning process: After 5 days, Sara has baked 5 days * 10 cakes / day = 50 cakes. After Carol's feast, there are 50 cakes - 12 cakes = 38 cakes remaining. Sara needs 2 cans / cake * 38 cakes = 76 cans of frosting.