An experiment consists of flipping a coin and then rolling a die What is the probability of observing a head on the coin or a 3 on the die?

The probability of flipping a Head is the same as that for a Tail and is 1/2 or 50%. The probability of rolling a particular number on a die is 1/6 since there are 6 numbers. Combining these two probabilities (by multiplication) we have, as the combined probability 1/2 x 1/6 = 1/12 = 0.0833333333333333(the 3 recurs) which as a percentage is 8.33333333333%