Math question

An honest coin is tossed three times in a row. Find the probability of each of the following events.

a.  E₁: "the coin comes up heads exactly twice."

b.  E₂: "all three tosses come up the same."

c.  E₃: "exactly half of the tosses come up heads."

d.  E₄: "the first two tosses come up tails."