The time a cell phone lasts until it needs to be recharged is normally distributed with a mean of 14 hours and a standard deviation of 3 hours.

a) You have to have your cell phone work for 10 hours as you are going on a hike. What is the probability the cell phone will not make the 10 hours necessary? (in other words what % cell phones last 10 hours or less before needing to be recharged)?

b) What percent of cell phones last over 18 hours before they have to be recharged?