how many of the positive factors of 16 are not factors of 20
"factors of 16 - 1 , 2 , 4 , 8 , 16 factors of 20 - 1 , 2 , 4 , 5 , 10 , 20 . comparing both , we have 2 factors of 16 which are not factors of 20 - 8,16 answer : a"
divide(20, 16)