A coin is tossed and a single 6-sided die is rolled. Find the probability of landing on the head side of the coin and rolling a 3 on the die.

There are two independent events:  (i) tossing a coin and
rolling 6 sided die.

When we toss an unbiased  coin we may
get a head or a tail up. So getting head or tail are equally likely . So the probability
getting a head = 1/2.

When an unbiased  6 sided die is
rolled , we may get any one of the number from 1 to 6. So there are 6 equal choices.
Getting 3 is one choice out of 6 choices. So the probability of getting 3 =
1/6.

Since the two events - getting a head in a coin in a
toss and getting  a 3 in a rolling of die - are independent , the happening of  both
events is the product of the probabilities = (1/2) (16) =
1/18.

Therefore , the probability of getting a head in a
toss of the coin and  getting a number 3 in a rolling of a die is
1/18.