Pls solve it

Suppose the response time X at a certain on-line computer terminal (the elapsed time between the end of a user's inquiry and the beginning of the system's response to that inquiry) has an exponential distribution with expected response time equal to 8 sec. (a) The probability that the response time is at most 10 seconds equal (b) The probability that the response time is between 3 and 12 seconds equal (e) The value of x for which the probability of exceeding the value 2% is