Missy had a giant piggy bank in her bedroom. Every day she would search the house for change to put in her bank. After 4 years, the bank was opened and it contained $450 in change. If the second, third, and fourth-year she doubled the amount of money she put in the bank from the amount she had put in the previous year, how much money, in dollars, did she put in the bank the first year?
Let's think: We let x be the amount of money she put in the bank the first year,. Then the second year was 2 * x,. and the third year was 2 * 2 * x = 4 * x,. and the fourth year was 2 * 2 * 2 * x = 8 * x. And the total amount she put in the bank, $450, is the sum of all four years, or $450 = x + (2 * x) + (4 * x) + (8 * x). This simplifies to $450 = 15 * x. And therefore, the amount of money she put in the bank the first year was x = $30.. The answer is: 30.

Sara is 6 inches taller than her brother Joe. Joe is 3 inches taller than his friend Roy. If Roy is 36 inches tall, how tall is Sara?
Let's think: Roy is 36 inches tall. Joe is 3 + 36 = 39 inches tall. Sara is 6 + 39 = 45 inches tall.. The answer is: 45.

Tracy, Michelle, and Kati take a road trip that is a total of 1000 miles. Tracy drives 20 miles more than twice Michelle, and Michelle drives 3 times the amount that Katie drives. How many miles does Michelle drive?
Let's think: Let x represent the number of miles Kati drives. Michelle:3x. Tracy:20 + 2(3x) = 20 + 6x. Total:x + 3x + 20 + 6x = 1000. 10x + 20 = 1000. 10x = 980. x = 98 miles. 3(98) = 294 miles.. The answer is: 294.

Mary has a mystery book library. She started with 72 mystery books at the beginning of the year. She joined a book club that sent her 1 book each month of the year. She went to a bookstore halfway through the year and bought 5 more books, then bought 2 books at yard sales later. Her daughter gave her another book for her birthday, and her mother gave her a series of 4 books when Mary visited her. She donated 12 books she didn't want to read again to a charity shop and sold 3 to a used book store. How many books did she have at the end of the year?
Let's think:
Mary got 1 * 12 = 12 books from the book club. She bought 5 + 2 = 7 books. She was given 1 + 4 = 5 books. She got rid of 12 + 3 = 15 books. Thus, at the end of the year she had 72 + 12 + 7 + 5 - 15 = 81 books.. The answer is: 81.