Hello, shaoen01!

3) If where are distinct primes,

In how many ways can n be expressed as a product of 2 positive integers?

( are considered the same)

What is the answer if ?

My comments:

From the solution, they mentioned the number of ways to choose a is which i understand.

It is stated that "it is a duplication by a factor of 2 since and both appear

as subsets but they give the same factorisation".

I do not understand where the duplication is.

Can somehow show me an example?

Suppose

With three factors to choose from, there are: possible subsets.

They are: .

But the question is: how many two-set partitions are there?

There arefour: .

The partition is the same as

. . because are the same factoring.