Question

Pre-Alg. Chapter 1 Question!

Mark plans to put concrete on a rectangular portion of his driveway. The portion is 8 feet long and 4 inches high. The price of concrete is $98 per cubic yard. The total cost of the concrete Mark needs is $58.07. Which of the following is closest to the width of the portion of the driveway on which Mark plans to put concrete?

Answer 1

(;_;)

Answer 2

Hi! I exist!

Answer 3

(u_u)

Answer 4

Wow. I'm getting ignored so much that I could put "terms and conditions" out of business. @Vocaloid can you help me?

Answer 5

convert the height and length to yards first

Answer 6

still there?

Answer 7

sorry my computer glitched up~ what do I convert to yards? 8ft long and 4in high?

Answer 8

allo? ._.

Answer 9

(~_~)

Answer 10

@tkhunny

Answer 11

It would help to draw a picture. Use the [Draw] button, below.

Answer 12

okey

Answer 13

yes, convert the dimensions to yards

Answer 14

convert 8 feet to yards
convert 4 inches to yards

Answer 15

4in = .11repeating yards.
8ft = 2.66667 yards

now what?

Answer 16

How do you calculate the volume of such a slab of concrete?

Answer 17

volume? I dunno

Answer 18

I don't believe that. Given Length, Width, and Height, what is the volume of the Rectangular Prism?

Answer 19

Wait, they gave the width?

Answer 20

No, they didn't. Just call it "Width". This is what the problem statement is asking. We must find it. Just write down the formula as if we know nothing, then fill in the pieces we know.

Answer 21

Oh okay. So is it length x height = width?

Answer 22

Where did the volume go?

Length * Width * Height = Volume

Fill in the ones we know.

Answer 23

Oh. So 2.6 * .11 * w = volume?

Answer 24

Try not to round so much.

8 ft = 2 2/3 yds = 8/3 yds

4 in = 4/36 yds = 1/9 yds

We have (8/3)(1/9)(Width)=(Volume)

Since we are given neither volume nor width, are we stuck?
Reading the problem statement again, we see:

"$98 per cubic yard. The total cost of the concrete Mark needs is $58.07."

Can we get volume out of that information?

Answer 25

Is the width less than a cubic yard? Because the total cost is less than the cost of the cubic yard

Answer 26

That's very good. We can use a proportion.

If 1 yd^3 costs $98.00, how many yds^3 creates $58.07?

Can you set up the proportion and solve for the necessary yds^3?

Answer 27

I don't think I know how to do that.

Answer 28

BTW -- "Is the width less than a cubic yard?"

Don't ever say that again. :-)

"width" is a linear measurement.
"cubic yard" is a volume measurement.
They are not particularly related. They certainly can't be equal, greater then, or less than.

It's like comparing 'x' to 'x^3'. You wouldn't add those, would you?

Okay, "Like Terms" side-bar concluded.

Answer 29

Define C = Number of Cubic Yards of Concrete

Then set up the proportion, \(\dfrac{1\;yd^{3}}{$98.00} = \dfrac{C\;yd^{3}}{$58.07}\)

Can you solve for "C"?

Answer 30

Not sure how

Answer 31

Multiply both sides by $58.07. This will do two things:

1) Get rid of everything but C on the RHS, and
2) Produce the result in the correct units on the LHS.

Answer 32

How do you multiply fractions?

Answer 33

You should know this. You WILL be required to do it on a test.

Right-Hand Side

\($58.07\cdot\dfrac{C\;yd^{3}}{$58.07} = C\;yd^{3}\cdot\dfrac{$58.07}{$58.07} = C\;yd^{3}\cdot 1 = C\;yd^{3}\)

Left-Hand Side

\($58.07\cdot\dfrac{1\;yd^{3}}{$98.00}= 1\;yd^{3}\cdot\dfrac{$58.07}{$98.00}\) -- You finish that. It's just a division problem for your calculator.