there are 7 red shoes & 3 green shoes . if two of red shoes are drawn what is the probability of getting red shoes
"taking 2 red shoe the probablity is 7 c 2 from 10 shoes probablity of taking 2 red shoe is 7 c 2 / 10 c 2 = 7 / 15 answer : d"
divide(choose(7, const_2), choose(add(7, 3), const_2))