00:02
Hey guys, in this problem, let n p is the number of seats, the airline reserves for the flight.
00:08
So let x is a random variable, denotes the number of passengers with reserved seats that arrive for the flight.
00:16
So x has a polynomial random variable with parameter n and p, such that p equals 0 .95.
00:26
Okay, so using the probability mass function of the polynomial random variable, so probability of the fall flight is that the probability of x where it's more than or equal 120.
00:39
So it's one minus probability of x less than 120.
00:44
Okay.
00:46
So it's one minus summation from x equals 0 to 119 for ncx times p power x times 1 minus 1 .1 .1 .1 .1 .1 .1 .4 .0.
01:00
For ncx times.
01:00
P for n minus x okay so let's find the minimum value of n such that the probability of a fall flight is at least 0 .9 such that probability of x more than or equal 120 more than or equal 0 .9 okay so using a computer software we find that n equal 1 to 1 okay so this is for probability of x more than or equal 120 it's 0 .0149 which is less than 0 .9 so using a computer software to find the probability of x more than or equal 120 for n equals 122 or 123 or 124...