Brittany uses 1/4 ounce of shampoo to wash her hair every other day. She buys shampoo in 14-ounce bottles. How many bottles does she need to get her through a leap year? Give the rationale and then the answer.
Let's think step by step. A leap year is one day shorter than a regular year, so it is 365 – 1 = 364 days. Brittany washes her hair every other day, so she will wash it 364 / 2 = 182 times in a leap year. A bottle of shampoo lasts her 14 / 1 / 4 = 14 * 4 = 56 washes. If she buys 3 bottles, she will only have enough for 56 * 3 = 168 washes. If she buys 4 bottles, she will have enough for 56 * 4 = 224 washes. Since 168 < 182 and 224 > 182, Brittany needs 4 bottles of shampoo to get her through a leap year.. The answer is: 4.

Lucas' father offers to pay him $2 for each window in the house that he cleans. Each floor of Lucas' house has 3 windows; Lucas lives in a 3-story house. To get Lucas to finish the job faster, his father tells him that he will subtract $1 for every 3 days that pass without Lucas finishing the job. In 6 days, Lucas finishes cleaning all the windows in the house. How much will his father pay him, in dollars? Give the rationale and then the answer.
Let's think step by step. Lucas cleans a total of 3 floors * 3 windows / floor = 9 windows. The windows cleaned earn Lucas 2 dollars each, so Lucas earns 9 windows * $2 / window = $18. For taking 6 days to clean, Lucas' father subtracts 6 days / $3 / day = $2. In total, Lucas' father will pay him $18 - $2 = $16.. The answer is: 16.

Greg is riding his bike around town and notices that each block he rides, his wheels rotate 200 times. He's now on a a trail and wants to make sure he rides at least 8 blocks. His wheels have already rotated 600 times, how many more times do they need to rotate to reach his goal? Give the rationale and then the answer.
Let's think step by step. They need to rotate 1,600 times because 8 x 200 = 1,600. They need to rotate 1,000 more times because 1,600 - 600 = 1,000.. The answer is: 1000.