# Math Help - Standard deviation

1. ## Standard deviation

The lifetime of a lightbulb is normally distributed with a mean life of 1000 hours and a standard deviation of 30 hours. Find the probability that a randomly selected lightbulb lasts longer than 1045 hours.

Using the bell curve, I get 6.7%, but I'm not sure if I'm right. Please let me know what the answer is and explain please!

2. correct as $P(Z>1.5) = .0668$

How is this trigonometry?