Question

In a box containing 10 bulbs, 2 are defective. What is the probability that among 5 bulbs chosen at random, none is defective?

Answer 1

Total number of bulbs = 10 

Number of defective bulbs = 2 

∴ Number of good bulbs = 10 – 2 = 8 

Now selecting 5 from the 10 bulbs can be done in ¹⁰C₅ ways.