Question 1119888
Three heads is (1/2)(1/2)(1/2) or 1/8
Two heads and a tail can occur 3 different ways, HHT HTH THH, so its probability is 3/8.
At least one tail is 1-no tails, which is 1-(1/8)=7/8
At least two heads is two heads (3/8 probability from above) and three heads, which is probability 1/8. The sum is 1/2.