Tabitha has 25 dollars. She gives her mom 8 dollars and invests half what is left in a money market. She spends some money on 5 items that costs 50 cents each. How much money does Tabitha have left? Give the rationale and then the answer.
Let's think step by step. Tabitha has 25 - 8 = 17 dollars after giving some to her mom. Tabitha has 17 / 2 = 8.5 dollars left after putting some in a money market. The 5 items Tabitha buys totals out to 5 * 0.5 = 2.50 dollars. Tabitha has 8.5 - 2.5 = 6 dollars left.. The answer is: 6.

Phil has 10 books that are all 100 pages each. He moves to a new home and during the move, 2 books are lost. How many pages worth of books does Phil have left? Give the rationale and then the answer.
Let's think step by step. Phil starts with 10 books and loses 2, for 10 - 2 = 8 books. Each of Phil's remaining books has 100 pages, so he has 8 * 100 = 800 pages worth of books.. The answer is: 800.

If Beth is 18 years old and her little sister is 5, in how many years would she be twice her sister's age? Give the rationale and then the answer.
Let's think step by step. The age difference between Beth and her sister is 18 - 5 = 13 years. Beth must be 13 x 2 = 26 to be twice her sister's age. Beth will be twice her sister's age in 26 - 18 = 8 years.. The answer is: 8.