#### allegansveritatem

##### Junior Member

- Joined
- Jan 10, 2018

- Messages
- 240

Here is the book's solution:

Here is what I did:

Question 1) Where did the author get the 4? The two largest numbers are 5 and 7 and the difference can only be 2 or -2.

Question 2) Is there a way to solve this problem using algebra? Or is that even expected here?