List the roots of f(x) = 24x3 – 10x2 -7x + 2:
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The question is incomplete. Here is the complete question.
Nite Time Inn has a toll-free telephone number so that customers can call at any time to make a reservation. A typical call takes about 4 minutes to complete, and the time required follows an exponential distribution. find the probability that a call takes
a) 3 minutes or less
b) 4 minutes of less
c) 5 minutes of less
d) Longer than 5 minutes
e) Longer than 7 minutes
Answer: a) P(X<3) = 0.882
b) P(X<4) = 0.908
c) P(X<5) = 0.928
d) P(X>5) = 0.286
e) P(X>7) = 0.174
Step-by-step explanation: <u>Exponential</u> <u>distribution</u> is related with teh amount of time until some specific event happens.
If X is a continuous random variable, probability is calculated as:
in which:
m is decay parameter, given by:
For the Nite Time Inn calls:
m = 0.25
(a) P(X<3)
P(X < 3) = 0.882
<u>The probability the call takes less than 3 minutes is 0.882.</u>
(b) P(X<4)
P(X < 4) = 0.908
<u>The probability the call takes less tahn 4 minutes is 0.908.</u>
(c) P(X<5)
P(X < 5) = 0.928
<u>The probability of calls taking less than 5 minutes is 0.928.</u>
(d) P(X>5)
Knowing that the sum of probabilities of less than and more than has to equal 1:
P(X<x) + P(X>x) = 1
P(X>x) = 1 - P(PX<x)
For P(X>5):
P(X > 5) = 0.286
<u>The probability of calls taking more than 5 minutes is 0.286.</u>
(e) P(X>7)
P(X > 7) = 0.174
<u>The probability of calls taking more than 7 minutes is 0.174.</u>