In how many ways can 2016 be expressed as the product of three integers, where the order of the factors matters?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
2016 can be factorized as 2 5 ∗ 3 2 ∗ 7 1 . If we need to arrange this into three factors, ( a 1 , a 2 , a 3 ) then we have a 1 ∗ a 2 ∗ a 3 = 2016. So each of a 1 , a 2 , a 3 can be expressed as powers of prime factors, a i = 2 x i ∗ 3 y i ∗ 7 z i . We have three equations ∑ i = 1 3 x i = 5 , ∑ i = 1 3 y i = 2 , ∑ i = 1 3 z i = 1 . Its easy to see the total number of possibilities are 7 c 2 ∗ 4 c 2 ∗ 3 c 2 = 378. Since the problem states 'integers', we need to consider the possibilities where 2 among a i 's are negative. So that gives us 3 c 2 more possibilities. So total = ( 3 c 2 + 1 ) ∗ 3 7 8 = 1 5 1 2