The probability that a player A wins a game against B is 0.7.The players may play either "a best of 3 games" or "a best of 5 games". If A has been asked to choose,
then which option should he choose,so that he wins the match?

You need to find the expected number of wins over 3 and over 5 games.

Expectation is given by

where n is the number of trials (games) and p the probability of winning the game.

Can you complete it now? The one with the higher expectation is the better.

Post what you get! :)

Can u explain it briefly

Let's have an example.

When you throw an arrow, you have a probability of 0.9 of hitting the bullseye. When you throw 10 arrows, you will expect that (10 x 0.9) = 9 arrows will hit the bullseye and 1 will miss. 9 is the 'winning' expectation.

Now you do the same with your problem.

The one where the expectation is the highest is the better.

The probability that a player A wins a game against B is 0.7.The layerd may play either "a best of 3 games" or a best of five games". If A has been asked to choose, then which option should he choose, so that he wins the match?