A box has 100 pens of which 10 are defective. What is the probability that out of a sample of 5 pens drawn one by one with replacement at most one is defective ?
1
\(\left(\frac{9}{10}\right)^5\)
2
\(\frac{1}{2}\left(\frac{9}{10}\right)^4\)
3
\(\frac{1}{2}\left(\frac{9}{10}\right)^5\)
4
\(\left(\frac{9}{10}\right)^5+\frac{1}{2}\left(\frac{9}{10}\right)^4\)