If the probability of her losing any drawing competition is 0.7, find the probability of her winning
a) at least one competition.

b) exactly two competitions.

In the first case, you have three entries out of 50, so your chance of winning assuming all drawings have equal chance of being picked is

In the first case, you have three entries out of 50, so your chance of winning assuming all drawings have equal chance of being picked is350=0.06.

In the first case, you have three entries out of 50, so your chance of winning assuming all drawings have equal chance of being picked is350=0.06.If you enter 3 contests 1 time, and I assume each contest is the same, then your chance of winning at least one of them is the complement to losing all of them. This probability is given by

In the first case, you have three entries out of 50, so your chance of winning assuming all drawings have equal chance of being picked is350=0.06.If you enter 3 contests 1 time, and I assume each contest is the same, then your chance of winning at least one of them is the complement to losing all of them. This probability is given by1−(4950)3=7351125000≈0.058808.

In the first case, you have three entries out of 50, so your chance of winning assuming all drawings have equal chance of being picked is350=0.06.If you enter 3 contests 1 time, and I assume each contest is the same, then your chance of winning at least one of them is the complement to losing all of them. This probability is given by1−(4950)3=7351125000≈0.058808.So it seems you have a slightly better chance of winning at least once if put all three of your bets in one contest.