DILIP
Last Activity: 7 Years ago
There are 20 ear rings in total. We have to select 4 ear rings in random.
In 20 pieces we can select 4 in 20C4 ways.
Total no.of outcomes are 20C4 = 4845.
Our favourable outcomes selecting at least one pair.
one pair can be selected from given 10 pairs in 10C1 ways.
Two pairs can be selected from given 10 pairs in 10C2 ways.
Total no.of favourable outcomes are 10C1 + 10C2 .= 100 + 45 = 145.
Probability = 145 / 4845 = 29 / 969.
