If 2 cubic feet of sand weigh 90 pounds, how much do 5 cubic feet of sand weigh?

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Answer 1 · 2017-03-11T17:53:33

#225# lbs

#2ft^3=90# lbs

#:.5ft^3=5/cancel2^color(red)1 xx cancel90^color(red)45/1# lbs

#:.5ft^3=225# lbs

#color(red)(check:#

#:.225lbs=5# ft^3

#:.90lbs=90/cancel225^45 xx cancel5^1/1# # ft^3#

#:.90lbs=90/45## ft^3#

#:.color(red)(90lbs=2 ##color(red)( ft^3#

Answer 2 · 2017-03-11T18:21:27

#225# pounds

This is a direct proportion, because as the volume of sand increases, the weight will increase.

#("ft"^3)/"pounds" = 2/90 =5/x#

#x = (90 xx5)/2#

#x = 225# pounds

Or, from the given information we can deduce that:

#1 "ft"^3# of sand weight #45# pounds.

Then

#5 "ft"^3# will weight #5 xx 45 = 225# pounds.