00:01
Hi, i'm david and i'm here to have you answer your question.
00:04
Now let me bring up your question here.
00:07
The probability that a person recovers from a royal blood disease is 0 .4.
00:12
So probability of the recover equal to 0 .4.
00:19
Now it will have n equal to the 15 people and let me remind you that if we have the x followed by the binomial with the n and the end and then the proper pt x equal to k equal to the n choose k b power k 1 minus p b b minus k now here if we call the x it will be equal to the number of the pupil that can recover and then we see x just followed by the the polynomial with the n equal to 15 be equal to the 0 .4.
01:07
Now in the part a the question asks you find the probability that at least 10 people survive so x will be greater equal to 10 this one just equal to the summation for the case starting from 10 up to the 15 and then we have the 15 it will apply the formula here it will be the 15 choose case and then 0 .4 power k 1 minus 0 1 .0 .0 power 50 minus k.
01:37
It will compute this one i will do it for you here and then we get equal to so it will equal to the 0 .033 8 and that's going to be the answer for the part i am the question.
02:03
Now for the part b we want to find the probability that the 3 to 8 people survive so x will be between the 3 to 8.
02:17
This one just equal to the summation 4k starting from 3 up to the value 8.
02:22
15 choose k, 0 .4 power k, 1 minus 0 .4 power 15 minus k...