three unbiased coins are tossed , what is the probability of getting at least 2 tails ?
"total cases are = 2 ^ 3 = 8 favoured cases = [ tth , tht , htt , ttt ] = 4 probability = 4 / 8 = 1 / 2 answer d"
negate_prob(divide(const_1, power(const_2, const_3)))