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A gallon of paint can cover 800 square feet.  Determine how many gallons should be purchased to paint two coats on each wall of a room which has dimensions 16 feet by 18 feet and an 8-foot ceiling.  how do I solve this problem?

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jeew-m eNotes educator | Certified Educator

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When you consider a room of length 18 width 16 and height 18 feet;

Area of floor `= 18*16 = 288 ft^2`

Area of ceiling `= 18*16 = 288 ft^2`

 

There are two smaller walls with height 8ft and width 16ft.

Area of smaller walls `= 2*16*8 = 256 ft^2`

 

There are two bigger walls with height 8ft and length 18ft.

Area of bigger walls `= 2*18*8 = 288 ft^2`

 

Total area to be painted `= 288+288+256 = 832 ft^2`

 

One gallon of paint cover `800 ft^2`

Gallons needed for one coat `= 832/800`

Gallons needed for to coats `= 832/800*2 = 2.08`

 

So you need 2.08 gallons for painting.

Note:

If you cannot buy 0.08 gallons (if shopkeeper doesn't give you less than 1 gallon) you should by another gallon. So...

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Luca B. eNotes educator | Certified Educator

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collegechristopher | Student

First you need to find out the square footage of the walls:

Add the width of all four walls to find the total width

16 + 16 + 18 + 18 = 68 feet

Now multiply the total width by the height of the ceiling to find the square footage of all the walls

68 feet x 8 feet = 544 square feet

Next, multiply the total square feet by two (two coats of paint)

544 x 2 = 1088

If one gallon of paint can cover 800 square feet, then you will need two gallons to paint the whole room