Check the picture below
should be pretty obvious how much silver is needed
just add the volumes
I think its 672 because * hrs a day is 56 and when you multiply that by 12 its 672<span />
2 is Negative because the fraction is negative. 3 is 978.6 gal changes per hour, I got this answer by subtracting 58,432.4 by 56,475.2 getting 1,957.2 and dividing that by 2.
It more resembles a pair of glasses.