Question

A manufacturer of laptops reports that among a shipment of 5000 sent to a local distributor, 1000 are slightly defective. If one purchases 10 of these laptops at random from the distributor, what is the probability that exactly 3 are slightly defective? 

Answer 1

Solution:

Given, $p=\frac{1000}{5000}=0.2$

$n=3, x=3$

$X\sim Bin(n,p)$

$P(X=3)=^{10}C_3(0.2)^3(0.8)^7=0.20132$