###Human: James prints out 2 books.  They are each 600 pages long.  He prints out double-sided and 4 pages per side.  How many sheets of paper does he use?, ### Assistant: He printed 600*2=1200 pages
Each sheet of paper was 4*2=8 pages
So he used 1200/8=150 sheets of paper 
 So the answer is :  150