Answer: 20 dogs
Explanation: The quickest way is to make a fraction of 26/40. 26 divided by 2 is 13 and 40 divided by 2 is 20.
The best way is to set up a proportion: 26 lbs/40 dogs=13 lbs/x dogs.
Cross multiplying (26*x and 13*40) leaves us with 520=26x.
When we divide both sides by 26, we find that 20 dogs is the answer.