# Probability that both defective lights will be found

A box contains two defective Christmas tree lights that have been inadvertently mixed with eight non-defective lights. If the lights are selected one at a time without replacement and tested until both defective lights are found, what is the probability that both defective lights will be found after exactly three trials?

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#### Solution Preview

There are total 2 + 8 = 10 light bulbs in the box.

to pick 3 out of 10, the total outcomes are: 10C3 = 10 * 9 * 8 / 3! = ...

#### Solution Summary

This solution calculates the probability that both defective lights will be found after exactly three trials.

$2.19