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 me reasons, before answering the question
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. So the final answer is 4.