00:01
This is a parallel question here, so the probability of success, which was given as 0 .19.
00:05
So for the first part of the question, what is the problem that you purchase, purchase exactly seven boxes? so that means n here, which is seven.
00:16
And you are going to just, you have to obtain two of the prizes here.
00:21
So that means for five of them, you couldn't obtain the price, and two of them you just obtain.
00:28
So the probability of these events, which is a period of getting two prizes.
00:36
So any of them should be the price here, which is seven two combination times.
00:42
This is 0 .9 to the power of 2 and times 1 minus 0 .19 to the power of 5.
00:49
7 2 combination, which is 7 times 6 over 7 times 6 over 2, which is 21 and 0 .19 to the power 2.
00:58
And 0 .81 to the power of 5, which is, this is 21 times 0 .19 to the power of 2 and multiply 0 .81 to the power of 5.
01:09
So the probability would be, which is 0 .26 and 43.
01:14
And what about b? at least 10 boxes here.
01:18
So the number of item here would be which is greater than or equal to 10 here...