These are independent events so the added probability is calculated by multiplying the two separate probabilities.
To get heads is 1/2
To roll 5 is 1/6
So P=1/2 * 1/6 =1/12
You get heads half of the times, since you have one, good outcome out of two.
Similarly, you get 5 on the die once every six times, on average.
These events happens simultaneously with probability [tex] \frac{1}{2}\cdot\frac{1}{6}=\frac{1}{12} [/tex]
