Use the Chebyshev's theorem and 1-(p(1-p)/(nc^2)) to verify that the probability is at least 35/36 that in 900 flips of a balanced coin the proportion of heads will be between 0.4 and 0.6

Mr F edit: Merged post from a new thread:

Use the Chebyshev's theorem and Binomial distribution to verify that the probability is at least 35/36 that in 900 flips of a balanced coin the proportion of heads will be between 0.4 and 0.6.