Amount Needed

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A deck is to be built with 2x4's 8 feet long.

Dimensions of deck:

8 feet wide.

30 feet long.

3/8" spacing between boards.

Boards are to be placed flat.

The board at the end can be cut lengthwise to fit, if needed, to blend in.

Calculate number of boards needed.

What is known:

Dimensions- 30 feet X 8 feet.

2X4's 8 feet in length.

3/8" spacing.

Want to know:

Number of boards needed to construct deck.

Let N= Number needed.

How do I proceed from here?

2 X 4's 8 feet in length.

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@Randy Dandy,

This is obviously homework.

By putting this stuff on various sites all over the place you probably run a good chance of getting a hit from one of them, so in the overall scheme of things you end up getting other people to do all the hard work for you, and then take the credit.

I forecast that you will be either a Merchant Banker, or a very successful politician.

Gawd bless the modern world.

1 Reply

@Lordyaswas,

Lordyaswas,

Not homework. I have been out of school over 30 years.

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@Randy Dandy,

You can buy those at Home Depot:

http://www.homedepot.com/catalog/productImages/400/6f/6f8c1b69-fa28-4cc7-bd4c-4e037c228ab3_400.jpg

2X4 Pressure treated lumber

Well, let X be the number of planks you need.

Then you have X-1 for the number of spaces, as you end with planks on both sides.

So, you know that 30 ft=360 in, right?

Then, the length of your deck contains 4X planks and 3/8(X-1) spaces.

It makes 360=4X+3/8(X-1).

Can you solve that for X?

2 Replies

@timur,

timur,

4X + 3/8(X-1)

4X + 3/8X - 3/8

4 3/8 X^2 - 3/8

That is not correct.

1 Reply

@Randy Dandy,

Indeed, what you wrote is not correct (no squares there).

Try again.

1 Reply

@timur,

No idea.

1 Reply

@Randy Dandy,

Then look here:

edit: "as you don't by planks" should be "as you don't buy planks"

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@timur,

timur,

I have read that a 2x4 is not actually a "2x4". When boards are rough sawn from the logs, they are 2x4's. After planed and smoothed, the dimensions are 1.5 x 3.5. They are referred to as 2x4's as are other dimensional lumber. So, the 1.5 x 3.5 would make a difference in the amount needed, correct?

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@Randy Dandy,

Obviously.

However, you just need to replace the "4" with the "3.5" and do the calculation as given above.

Good luck with your deck.

1 Reply

@timur,

Thanks timur.

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