1) Let's enlist all the possible outcomes. H-Heads, T-tails. If we toss two coins penny and a nickel then we would have:
(t,t) (h,t) (t,h) and (h,h) 4 total outcomes
2) Since we want to know the chance of getting tails, then we'll call tails our favorable outcome. From the total outcomes, we can count that there is only one possibility:
(t,t) (h,t) (t,h) and (h,h) 1 favorable outcome
(t,t) so we can write:
Thus, this is the answer 1/4