what is the greatest value of x such that 4 ^ x is a factor of 21 ! ?
pretty simple , really . if m = 6 , then 4 m = 24 , which is 12 x 2 , both of which are included in 21 ! since 6 is the largest number here , its the answer . answer is b
add(divide(subtract(21, const_1), 4), const_1)