If 1/2 of the air in a tank is removed with each stroke of a vacuum pump, what fraction of the original amount of air has been removed after 2 strokes ?  Select the correct option:	A) 3/4	B) 7/8	C) 1/4	D) 1/8	E) 1/16
Left 3/4fter 1st stroke = 1/2   Left 3/4fter 2nd stroke = 1/2 * 1/2 = 1/4   So removed = 1- 1/4 = 3/4
<result>A</result>
If 1/2 of the air in a tank is removed with each stroke of a vacuum pump, what fraction of the original amount of air has been removed after 2 strokes ?