Joe is painting a rectangular room whose dimensions are given by a, b and c meters. Joe takes 8 hours to paint a wall with dimensions a and c. He takes 4 hours to paint a wall with dimensions b and c and 12 hours to paint the ceiling with dimensions a and b. If Joe works at a constant rate and a = 7, then what is the volume of the room?
Choose the correct choice from the following choices:	A) 18 cubic meters	B) 24 cubic meters	C) 30 cubic meters	D) 36 cubic meters	E) 57.1 cubic meters
Time to paint each wall as given in problem:   AC = 8 hours   BC = 4 hours   AB = 12 hours   Since he works at constant rate and it takes him twice as long to paint AC compared to BC   AC=2BC   Plug in 6 for A and you find that B=3.5   Since painting AB takes 3 times as long compared to BC,   AB=3BC   Plug in 6 for A and 3 for B and you find that C=2.33   A*B*C=7*3.5*2.3=57.1 cubic meters   Answer: 57.1 cubic meters
<result>E</result>
Joe is painting a rectangular room whose dimensions are given by a, b and c meters. Joe takes 8 hours to paint a wall with dimensions a and c. He takes 4 hours to paint a wall with dimensions b and c and 12 hours to paint the ceiling with dimensions a and b. If Joe works at a constant rate and a = 7, then what is the volume of the room?