A side of beef lost 20 percent of its weight in processing. If the side of beef weighed 640 pounds after processing, how many pounds did it weigh before processing?	Choose the correct choice from the following answers:	A) 191	B) 355	C) 800	D) 840	E) 900

Rationale: "let weight of side of beef before processing = x ( 80 / 100 ) * x = 640 = > x = ( 640 * 100 ) / 80 = 800 answer c"
Answer: C