math question?

Question

Find the number of odd divisors of 7!.

If you understand how to do this, please show me how. Thanks

Answer 1

No of odd divisors of : 1.2.3.4.5.6.7
There is a 3 in 6.
the odd product can be only chosen from 3,3,5,7
There are 16 possible product combinations that we can make from 3,3,5,7 (by chosing an odd or not choosing an odd in the product)
We also have to include 1
So Answer = 17 ,including 1 as odd divisor

Answer 2

7! (7 factoral) = 7*6*5*4*3*2*1 = 5,040
So, we now need to find how many odd numbers can be divided into 5,040...
WE'll start with the obvious ones...1,3,5,7
Now we can try multiplying 2 of the numbers together and those products which are odd numbers will also be divisors
(i.e. 3*5 = 15, so 15 would be another one)
So, now we would have 1,3,5,7, then (3*3),(3*5),(3*7),(5*5),(5*7),(3*5*7)
Only an odd number multilpied by another odd number will yield an odd-numbered product
So, we have 1,3,5,7,9,15,21,25,35,and 105 as divisors
10 divisors total

Hope that helps :)

Answer 3

First of all, Jasper's work has an error. 25 is not
a divisor of 5040. The correct answer is 9 odd factors.
Why? Well, 1,3,5,7 are clearly odd divisors.
Since 3² divides 5040, but 25 and 49 don't,
we get the rest of them
by pairing 3,5,7 with every other one but only 3
with itself and we must also add 3*5*7= 105
to the count.
So our list is 1,3,5,7,9, 15,21,35 and 105.

Answer 4

23 AND TWO THIRDS EQUALS 71 BECAUSE 23x3 =69 plus 2 thirds x3 =2 more there ya go

Answer 5

W#hole (1,3,5,7.....)