Suppose That the Random Variable X Has an Exponential Distribution $x$

Suppose that the random variable x has an exponential distribution with θ = 3. a. Find the probability that $x$ assumes a value more than three standard deviations from $\mu$ .
b. Find the probability that $x$ assumes a value less than one standard deviation from $\mu$ .
c. Find the probability that $x$ assumes a value within a half standard deviation of $\mu$ .