A fort of 4000 soldiers has provisions for 100 days. After 20 days some of them left and the food was now enough for the same period of 100 days as before. How many of them left?
Choose the correct answer:
A) 650	B) 700	C) 750	D) 800	E) 850
2000 ---- 50   4000 ---- 80   x ----- 100   x*100 = 4000*80   x=3200   4000   -------   800   Answer: 800
<result>D</result>
A fort of 4000 soldiers has provisions for 100 days. After 20 days some of them left and the food was now enough for the same period of 100 days as before. How many of them left?