In a multiple choice question paper with four options, getting the answer right with the first guess (that is, if we don't know the answer) has a probability of . What are are the probabilities for getting the correct answer on the second, third or fourth guesses?
The probability of getting it right on the first guess is ¼ as already stated. On second guess it's so the same. For the third guess, so same again and the forth isn't a guess as it's the last one remaining with a probability of, you guessed it, .
So guessing wrong doesn't improve your chance of guessing right at any point.