surface area of a room

OP

Original post by DFranklin

Post your working.

(Also note the 2 coats, and allow for the fact that the answer may take into account that you can only buy full tins of paint. So if you calculate you need 4.5 tins of paint (for example), then you actually need to buy 5 tins).

What does actually mean 2 coats of paint??

Reply 3

DFranklin

18

Original post by Alen.m

What does actually mean 2 coats of paint??

It means everything gets painted twice. (You have obviously never painted a room!)

Reply 4

OP

Original post by DFranklin

It means everything gets painted twice. (You have obviously never painted a room!)

Yeah never needed to! So basically you devided the totall area surface of the room by 20 to find out how many tin of paint you need to cover the whole room?

Reply 5

DFranklin

18

Again, you need to allow for painting it twice...

Reply 6

OP

Original post by DFranklin

Again, you need to allow for painting it twice...

How would you explain that mathematically? Like the number of tins need to be devided or multiplied by 2?

Reply 7

old_engineer

Original post by Alen.m

Yeah never needed to! So basically you devided the totall area surface of the room by 20 to find out how many tin of paint you need to cover the whole room?

I think the question refers to painting the walls, whereas you have included the walls, floor and ceiling...

Reply 8

old_engineer

Original post by Alen.m

How would you explain that mathematically? Like the number of tins need to be devided or multiplied by 2?

1) Determine the surface area to be painted;

2) Work out how much paint is needed for one coat of the area from (1), based on the given coverage information for the paint;

3) Multiply by 2 to give the amount of paint needed for two coats;

4) Divide by the amount of paint contained by one tin, to determine how many tins of paint are needed;

5) If the answer to (4) is not an integer, round it up t the next integer.

Reply 9

OP

Original post by old_engineer

1) Determine the surface area to be painted;

2) Work out how much paint is needed for one coat of the area from (1), based on the given coverage information for the paint;

3) Multiply by 2 to give the amount of paint needed for two coats;

4) Divide by the amount of paint contained by one tin, to determine how many tins of paint are needed;

5) If the answer to (4) is not an integer, round it up t the next integer.

I've ignored the celling and floor as you've suggested but the answer still not correct

Reply 10

It would help if you didn't paint the floor and ceiling and got the room dimension right. It is 9.8m long, not 9.2m.

Reply 11

OP

Original post by Good bloke

It would help if you didn't paint the floor and ceiling and got the room dimension right. It is 9.8m long, not 9.2m.

It's actually 9.2m...

Reply 12

Carthaginian

2

Original post by Alen.m

It's actually 9.2m...

In your OP you wrote 9.8, not 9.2.

Reply 13

Original post by Alen.m

It's actually 9.2m.

You told us, in the OP, that it is 9.8m.

Reply 14

OP

Original post by Good bloke

You told us, in the OP, that it is 9.8m.

yeah my bad :frown:

... i'll edit it now . it shouldn't be that complicated as it's only a grade C question. I don't know why i cant get it right tho :frown:

Reply 15

I suspect you cannot do multiplication very well the answer is 8 cans exactly, though I see your picture shows you are painting the ceiling and floor but neither of the narrow ends.

Reply 16

OP

Original post by Good bloke

I suspect you cannot do multiplication very well the answer is 8 cans exactly, though I see your picture shows you are painting the ceiling and floor but neither of the narrow ends.

even with the 8 cans, the answer would still be wrong.
8x11.75=94 (the answer is 96)

Reply 17

Original post by Alen.m

even with the 8 cans, the answer would still be wrong.
8x11.75=94 (the answer is 96)

There is no whole number of cans that costs £96 if the unit price is £11.75. Are you sure you read the answer correctly?

(edited 7 years ago)

Reply 18

elekro

13

Original post by Alen.m

Hi guys,
I'm struggling in question below if anyone can give me a hint would be perfect.
A room has dimensions 6.8 metres x 9.2 metres x 2.5 metres. Stephanie wants to paint the walls of the room,. A large tin of paint covers 20m^2 and costs 11.75. Ignoring windows and doors and allowing for two coats of paint, how much will it cost Stephanie to paint the room?
so basically what i've done was calculating the area surface of the room and divide it by 20 to find out how many tins of paint we need to paint the room and then multiply that by 11.75 which gives me a wrong answer.

so the walls alone(without ceiling and floor, as the problem states that Stephanie wants to paint just the walls) are 80m^2 (because two walls are 9.2x2.5 and the others are 6.8x2.5). So for one coat of paint you need 4 tins, thus for two coats you need 8 tins, which will cost you 94 pounds.

Reply 19