Question

Find all pairs of consecutive even positive integers, both of which are larger than 8, such that their sum is less than 25.

Answer 1

Let the smaller even integer be x (> 8).

Then the next is x + 2 and their sum is 2x + 2 < 25, so 2x < 23 

⇒ x < 11.5

Since x is an even integer > 8, the only possibility is x = 10. 

Thus the pair is 10 and 12.