help pls

1) Let the random variable X represent the length of time (in minutes) between calls to an emergency number in a small town. Assume that the calls come in to the switchboard according to a Poisson process at the rate of one call per ten minutes. What is the probability that the waiting time until the arrival of the first call after 10 AM is greater than 20 minutes? Solve this problem by (a) the exponential distribution (b) the Poisson distribution 2) If the continuous random variable X has probability density function: f(x) = Cif 1