Answer:
a) 0.1353
b) 0.3679
Step-by-step explanation:
Let's start by defining the random variable T.
T : ''The time (in hours) required to repair a machine''
T ~ exp (λ)
T ~ exp (1)
The probability density function for the exponential distribution is
(In the equation I replaced λ = L)
With L > 0 and x ≥ 0
In this exercise λ = 1 ⇒
For a)
For b)
The event (T ≥ 10 / T > 9) is equivalent to the event T ≥ 1 so they have the same probability of occur