Problema Solution
A coin is tossed 5 times. Find the probability that at most 2 are heads.
Answer provided by our tutors
P (At most 2 Heads) = P (2H) + P (1H) + P (0H) =
= C(5,2) ((1/2)^2)*((1/2)^(5 - 2))) + C(5,1) ((1/2)^1)*((1/2)^(5 - 1))) + C(5,0) ((1/2)^0)*((1/2)^(5 - 0))) =
= 10*(1/2)^5 + 5*(1/2)^5 + 1*(1/2)^5 = 16*(1/2)^5 = 1/2 = 0.5 or 50%.