A biased coin has probability 0.3 of landing heads. The coin is tossed five times.
Use a term in the expansion of (0.3+0.7)5(0.3+0.7)^5(0.3+0.7)5 to find the probability of obtaining exactly two heads.
108 exam-style questions on OCR A Level Maths 1.4.1 Binomial expansion for positive integer n. Each one has a worked solution and a mark scheme showing where the marks go.