SOLUTION: Ok, here is my 6th grade daughter's problem: Anne is sealing blocks measuring 8 in by 9 in by 12 in. A can of sealant covers 20 square feet. How many cans should Anne buy for

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Question 609738: Ok, here is my 6th grade daughter's problem:
Anne is sealing blocks measuring 8 in by 9 in by 12 in. A can of sealant covers 20 square feet. How many cans should Anne buy for 12 blocks?
We have calculated the surface area of the rectangular block to be 552 in sq. If a can covers 240 in sq (20 sq feet =240 sq inche?) then we would divide 552 by 240 and would need 2.3 cans per block and mulitply by 12 blocks which would equal 27.6 rounded up to 28 cans. Is that correct? The 20 square feet versus inches squared is throwing me off. THANK YOU!
GC
Answer by Earlsdon(6287) (Show Source):
You can put this solution on YOUR website!
Your first part is correct:
The total surface area of one of the blocks is 552 sq.in.Now 1 can of sealant covers 20 sq.ft.
And 20 sq.ft. = 20*144 = 2880 sq.in. because there are 144 sq.in. in one sq.ft.
So each can of sealant covers 2880 sq.in.
For the 12 blocks, the total surface area is: 552*12 = 6624 sq.in.
So you need to divide the total surface area to be covered, that's 6624 sq.in by the coverage for one can, that's 2880 sq.in.
cans of sealant would cover all 12 blocks.