Answer:
Ok so i hope this helps you.
There are 56 dogs when the number of cats is 140.
Explanation:
The ratio of dogs to cats:
 \frac{2}{5} 
The other proportion:
 \frac{x}{140} 
 \frac{2}{5} = \frac{x}{140} 
5 times 28 is 140.
Multiply the fraction by the appropriate form of 1
 \frac{2}{5} * \frac{28}{28} = \frac{56}{140} 
There are 56 dogs when the number of cats is 140.