45 % customers purchase ordinary TV set and 15% customers purchase HD TV set. This means that 60% customers purchase either an Ordinary set or a HD set.

If 5 customers enter the store, then 3 will purchase either of the two types of sets and 2 customers will be just observers.

Probability of selling 2 ordinary sets will thus be 2/3 and probability of selling 1 HD set will be 1/3.

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