what is the probability of getting exactly 1 head in a single throw of five fair coins ?
"one possible case is htttt . p ( htttt ) = 1 / 2 * 1 / 2 * 1 / 2 * 1 / 2 * 1 / 2 = 1 / 32 there are 5 c 1 = 5 possible cases . p ( 1 head ) = 5 * 1 / 32 = 5 / 32 the answer is d ."
divide(const_2, choose(add(const_3, const_3), const_3))