if n is the product of the integers from 1 to 20 inclusive, what is the greatest integer k for which 2^k is a factor of n ?

a. 10 b.12 c.15 d.18. e.20

ans. d

how do i get the answer ?

in a corportation , 50 percent of the male employees and 40 percent of the female employees are at least 35 yrs old. if 42 percent of all the employees are at least 35, what fraction of the employees in the corporation are females ?
ans .4/5

thanks;)