You can put this solution on YOUR website! Assume that both coin and die (6-sided!) are fair. Otherwise, adjust the probabilities accordingly.
P(H) = 1/2, P(even) = 1/2, and P(H & even) = .
==> the probability of obtaining heads or an even number would be
P(H or even) = P(H)+ P(even) - P(H & even) = 1/2 + 1/2 - 1/4 = 3/4.