Answer:
n and (n - 1) are consecutive integers.
Step-by-step explanation:
We are given 'n', a positive integer.
This 'n' can either be odd or even.
Case I:
When 'n' is odd
The n - 1 is even.
Note that the product of odd and even is always even. That is the product of n and (n - 1) is even.
Case II:
when 'n' is even
Then n - 1 is odd.
Again, using the similar logic we can say that the product of n and n - 1 should be even because here, 'n - 1' is even and 'n' is odd.