A person has a bag which contains 9 bulbs out of which 2 are fused and cannot be used to lighten the room. Two bulbs are selected at random. What is the probability that all the two bulbs chosen can be used to lighten the room ?
Probability = Number of favourable cases/ total number of cases
favourable cases=Â $$7_{c_2}$$Â
total cases =Â $$9_{c_2}$$
Probability =Â $$\frac{\left(7c_2\right)}{\left(9_{c_c}\right)}$$ =7/12
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