Probability: A box contains 20 components of which 15 are good and 5 are faulty.

Hi everyone,

I am looking for some advice on how to calculate the answer to this probability calculation.

(b) A box contains 20 components of which 15 are good and 5 are faulty. If 3 components are chosen at random from the box, find the probability that at least 2 are good.

Guitar_99 said:

Hi everyone,

I am looking for some advice on how to calculate the answer to this probability calculation.

(b) A box contains 20 components of which 15 are good and 5 are faulty. If 3 components are chosen at random from the box, find the probability that at least 2 are good.

Click to expand...

Find the ways to choose 3 out of 20. = N

Find the ways to choose 3 out of 20 where all three are good = N₃

Find the ways to choose 3 out of 20 where exactly two are good = N₂

Probability of choosing at least 2 good component = (N₂ + N₃)/N

What are your thoughts?

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