A container has a capacity of 30 gallons and is full of spirit. 4 gallons of spirit is drawn out and the container is again filled with water. This process is repeated 5 times. Find how much spirit is left in the resulting mixture finally?	Answers
A) 6(257/525) gallons B) 6(346/625) gallons C) 6.5 gallons D) 6.25 gallons E) None of these
There is a direct formula to calculate such repetition:   Left QTY / Orig QTY = ( (Orig QTY - Rep QTY) / Orig QTY )^n   where n is number of times mixing done:   Left QTY / 30 = (30 -4)^5 / 20^5   Left QTY = 30 (26/20)^5   Left QTY = 30 ( 13/10 )^5   Left QTY = 74.2586   Answer is None of these
<result>E</result>
A container has a capacity of 30 gallons and is full of spirit. 4 gallons of spirit is drawn out and the container is again filled with water. This process is repeated 5 times. Find how much spirit is left in the resulting mixture finally?