An Appliance Comes with an Unconditional Money Back Guarantee for Its

Short Answer

An appliance comes with an unconditional money back guarantee for its first 6 months. It has been found that the time before the appliance experiences some sort of malfunction is an exponential random variable with mean 2 years. What percentage of appliances will malfunction during the warranty period? Enter your answer as just a ± $\mathrm { e } ^ { \mathrm { b } }$ , where a is an integer and b is a real number to two decimal places. (no units).