Answer:
-7 degrees
Step-by-step explanation:
Make sure to double check, but I think this is the answer.
Answer:
a) P(t>3)=0.30
b) P(t>10|t>9)=0.67
Step-by-step explanation:
We have a repair time modeled as an exponentially random variable, with mean 1/0.4=2.5 hours.
The parameter λ of the exponential distribution is the inverse of the mean, so its λ=0.4 h^-1.
The probabity that a repair time exceeds k hours can be written as:

(a) the probability that a repair time exceeds 3 hours?

(b) the conditional probability that a repair takes at least 10 hours, given that it takes more than 9 hours?
The exponential distribution has a memoryless property, in which the probabilities of future events are not dependant of past events.
In this case, the conditional probability that a repair takes at least 10 hours, given that it takes more than 9 hours is equal to the probability that a repair takes at least (10-9)=1 hour.


Answer:
3.8%
Step-by-step explanation:
90/2358=0.038
Note --> As you're writing 'zeroes' , I assume there is a typing mistake and you've given a Quadratic equation in the question

Hence , the roots are 1/2 and -6
The graph attached confirms the same ,
Hope it helps you :)