A fort of 2000 soldiers has provisions for 50 days. After 10 days some of them left and the food was now enough for the same period of 40 days as before. How many of them left?  Choose the correct choice from the following:
A) 100	B) 0	C) 200	D) 400	E) 500
2000 ---- 50   2000 ---- 40   x ----- 40   x*40 = 2000*40   x=2000   2000   -------   0   ANSWER:0
<result>B</result>
A fort of 2000 soldiers has provisions for 50 days. After 10 days some of them left and the food was now enough for the same period of 40 days as before. How many of them left?