The probability of picking red button is
<u>Solution:</u>
Given, A jar contains 30 red, 30 blue, and 60 white buttons.
You pick one button at a random choice,
We have to find the probability that it is red button.
Now, total number of buttons = 30 + 30 + 60 = 120 buttons.
Number of favourable cases for red button = 30 red buttons.
The probability of an event is given as:
Thus the probability that it is red is
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.