homework help please?

Question

I just cannot solve this problem. Can you please help and tell me how to solve it?

At 2 cents a square foot, what will it cost to plaster the walls and ceiling of a room 16 ft long, 12 ft wide, 14 ft high, deducting for two doors each 8ft x 4 ft and for three windows each 7 ft x 3 ft?

Answer 1

find the total surface area of the room

SA = 2(area of the base) + perimeter of the base * height

SA = 2(16*12) + 2(16+12)*14

SA = 1,168ft^2

You need to subtract the area of the doors, the window from and the area of the floor from the area surface area of the room because you don't need to plaster them.

Area(door) = L * W
A = 8 x 4
A = 32ft^2

there are 2 of them: 2(32) = 64ft^2

Area (windows) = L * w
A = 7 x 3
A = 21 ft^2

there are 3 of them: 3(21) = 63ft^2

Area(floor)
A = 16*12
A = 192ft^2

1,168ft^2 - (63ft^2 + 64ft^2 + 192) = 894ft^2

894ft^2 * $.02 / 1ft^2 = $16.98

Answer 2

1(16 x 12) + 2(16 x 14) + 2(14 x 12) - 3(8 x 4 ) - 3(7 x 3 )
NB 1 ceiling (NB its corresponding face is the floor which is not plastered.
2 walls
2 walls
2 doors
3 windows
So!!!!
192 + 448 + 336 - 96 - 63 sq. ft.
817 sq. ft. x 2 cents =
1634 cents
16.34 Aus. dollars

Answer 3

First, figure out how many square feet you need. The entire interior surface to be plastered consists of:

a - two walls that are 16ft long by 14ft high
b - two walls that are 12ft long by 14ft high
c - a ceiling that is 16ft by 12ft

The area associated with the a is 2(16x14sq-ft) = 448sq-ft.
The area associated with the b is 2(12x14sq-ft) = 336sq-ft.
The area associated with the c is 16x12sq-ft = 192sq-ft.

This totals up to (448+336+192)sq-ft = 976sq-ft.

However, there are two door and three window spaces that need to be subtracted. Each door is 8ft by 4ft and each window is 7ft by 3ft.

The doors give area of 2(8x4sq-ft) = 64sq-ft.
The windows have area of 3(7x3sq-ft) = 63sq-ft.

This totals to (64+63)sq-ft = 127sq-ft to remove.

Hence, the total to plaster is: (976-127)sq-ft = 849sq-ft.

at a price of 2 cents per sqare foot, the total cost is:

(849sq-ft)x($.02/sq-ft) = $16.98

Answer 4

Questions like this seem complex, but the best way to approach them is to break them down into sections. In this case, you have four wall, a ceiling, three windows, and two doors. Sometimes people want to jump right to 'simplification' of algebra, but this is a bad approach. It makes it harder to get to the answer. You know each wall is 14 feet high. So, calculate the four walls height and width to get area like this (12x14)+(12x14)+(16x14)+(16x14). Now you have the walls done. Note this number. Now, the ceiling is (12x16). Note this number. Now calculate each door (8x4)+(8x4). Note this number. Finally, calculate the windows like this (7x3)+(7x3)+(7x3). Note this number. Now, take the ceiling number, plus the wall number and add them together. This is the total area of the room. Now take the door number and add the window number. This is the total area that needs to be subtracted. Now take the total room area minus the door and window number. Boom! Take this answer time 2 cents.

It's not a hard problem, but just remember that with this or any other math problem, break down the problem into its pieces, then solve each piece, then bring the pieces back together. Once you feel comfortable, try to simplify repeating calculations.

Good Luck!!!

Answer 5

1. times the 14, 12, and 16 together (to get the area/volume of the room)
14 x 16 x 12=2688

2. find the area of the windows and doors.
8 x 4=32 (window)
7 x 3=21 (door)

3. add all the window and door area's together.
32 + 32=64 (Doors)
21 + 21 + 21=63 (windows)
64 + 63=127 (both combined)

4. subtract the doors and windows from the total of the room.
2688 - 127=2561 (the walls, with no windows or doors)

5. multiply 2561 by $0.02, which will give you the answer.
2561 x $0.02= $51.22 (how much it will cost to plaster the wall)



the answer is $51.22

Answer 6

Find the area of the room. Find the area of 1 door, multiply it by 2, and then add that to 3 times the area of the windows. Take that and multiply it by 2. That'll give you yer answer! Hope that helps!!! Good luck!