Last week Fred had 27 dollars and Jason had 27 dollars. Fred washed cars over the weekend and now has 13 dollars and Jason did not work. How much money do they have together now?
Fred had 27 dollars and Jason had 27 dollars. 

That means that, together, they had 54 dollars. 

Fred washed cars over the weekend and now has 13 dollars. 

That means that he spent 14 dollars while washing cars. 

Jason did not work. 

That means that he still has 27 dollars. 

Now, let's put it all together. 

Fred has 13 dollars and Jason has 27 dollars. 

That means that, together, they have 40 dollars.