Automobile warranty claims for engine mount failure in a troppo malo 2000 se are rare at a certain dealership, occurring at a mean rate of 0.1 claim per month. (a) what is the probability that the dealership will wait at least 6 months until the next claim

The probability that the dealership will wait at least 6 months until the next claim is solved by:We know that the mean number of occurrences per time unit is 0.1, then let’s denote this by λ
So: f (x) = 1 – e ^ -λx for x > 0
P (x > 6) = e^ -x
= e ^-0.1 * 6
= 0.5488

Its equal to d=7.07in