The company Colonel Electric has produced a new brand of lig

The company Colonel Electric has produced a new brand of light bulb.
Suppose that x measures the number of hours elapsed before one of these light bulbs
fails. The probability density function for x is given by
p(x) = 200e
cx
for x 0 (and 0 otherwise)
where c is a constant.
(a) What is the value of c?
(b) What is the probability that a light bulb lasts for more than 50 hours?
(c) What is the median value of the number of hours these light bulbs last?