I'm lost, so I'd greatly appreciate as much detail as possible. Thank you!

Consider the exponential distribution which is used to model the duration of intervals between successive occurrences of a random event. The probability density function is 151320 f(t;/1)={O 3K0 where 7L is a positive constant. For this distribution, the mean and standard deviation oft are ,u= 0'= 1/7. a) Determine the probabilities pm