There are 4 copies of 5 different pens. In how many ways can they be arranged on a shelf?	Choose the correct choice from the following:
A) 20!/4! B) 20!/5(4!) C) 20!/(4!)^5 D) 20! E) 5!
There are 4 copies of 5 different pens.20!/((4!)^5)   Answer - 20!/(4!)^5
<result>C</result>
There are 4 copies of 5 different pens. In how many ways can they be arranged on a shelf?