Comparing Continuous Distributions

The lifetime of one of DotCom's electronic equipment has a mean of 400 hours and standard deviation of 400 hours. They have been assuming lifetime is normally distributed. What is the probability that equipment operates for more than 500 hours before failure?

DotCom is puzzled because experience indicates that this probability should be smaller. Explore using the Exponential distribution, which is also a good model for failure rates. Compare the probability that equipment operates for more than 500 hours before failure with the Exponential distribution. Give a recommendation to DotCom