Question

If there are 10 computers left in the electronics store to sell, and 6 are laptops, 4 are desktops. Consider we are interested in the next five computers sold.

1. What is the probability that at least 4 of the next 5 computers sold are laptops?

2. What is the probability that all of the next 5 computers sold are laptops given that we know the next two sold will be laptops?

Answer 1

1) Probability that atleast 4 of the next 5 desktop sold are laptops =

Let the number of laptops be x.

Probability of having a laptop =

So, P(X>=4) = P(X=4)*5C4 + P(X= 5)

= (6/10)*(5/9)*(4/8)*(3/7)*(4/6)*5 + (6/10)*(5/9)*(4/8)*(3/7)*(2/6)

= 0.238 + 0.0238

= 0.2618

2) Probability that all the next 5 desktops will be laptops when it is given that the first 2 are laptops=

P(X=5|X=2) = ((6/10)*(5/9)*(4/8)*(3/7)*(2/6)) / ((6/10)*(5/9))

= 0.0714.

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