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Hi Scott,

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

Dimensions of deck- 30 feet long, 8 feet wide with 3/8" spacing.

The last board could be cut lengthwise to fit if necessary, resulting in a smaller width board and would blend in.

How many 2x4's were purchased ?

Thanks for your assistance.

Sorry about the delay ...

If a 2x4 were really 2" by 4":

If it is 8 feet wide, then since 8*12 = 96, it is 96 inches wide.
If a 2x4 we really 2" by 4", and they were lay flat, the width of each would be 4" and there would be a 0.375" spacing between them.  Since 96/4.375 = 21.94285714,
that would imply we needed 22 rows of 2x4's.

Since the deck is 30' long, and 30/8 = 3.75, we would need 3.75 2x4's for each row.

The total would then be 3.75 x 22 = 82.5, which is really 83 2x4's.

In carpentry, 2x4's, like a lot of other things, are measured before being smoothed out.
Last I knew, the real size of 2x4's is 1.5 * 3.5:

Since they are really 3.5" wide, adding on the 0.375 gives 3.875,
and 96/3.875 = 24.7, which would be 25.
The answer would then be 3.75 x 23.7 = 92.625,
so we would need 93 2x4's.


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Scott A Wilson


Any algebraic question you've got. That includes question that are linear, quadratic, exponential, etc.


I have solved story problems, linear equations, parabolic equations. I have also solved some 3rd order equations and equations with multiple variables.

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