Mathematical Problem - Please Explain!

[gambit]

I am not a genius, nor am I a dummy, but this has me completely befuddled!!!


I am figuring for 2 concrete slabs.

Each of these slabs has a dimension of 13 ft x 7 ft x 0.333

find the volume for cubic yards which will be divisible by 27

Now double your answer and place your numbers on a new reply with the below answer.

HERE IS WHERE IT GET'S WEIRD!!!

Double the amount of your measurements 13(2) = 26 Do the same for the 7. 7(2)= 14

The thickness of the concrete never changed so that remains constant. ( 0.333)
find the volume for cubic yards which will be divisible by 27

So the equation should look like this: 26 x 14 x 0.333=

Place your answer and tell me why it is different.

Is there a step I am missing?

[Gary Brown]

You are making the mistake of doubling the 13 and 7. Do your 13x7 and double it at the end to get your 2 slabs.

If your double it first your are probably getting 4x instead of 2x.

Draw a square on a piece of paper, now draw another the same size under it. You have another demension constant besides the depth. It can be length or width.

Did I get it right?

[gambit]

I had posted a reply before I saw your edit.

That is exactly what is happening. The numbers actually quadruple when you double the size of the slab.


SO, I should just figure for each slab individually...

[JD Slough]

I would say each slab individually. If you double then multiply again you will be way off, do each one as an individual, especially if you are pouring side by side

Gary, now not only do you have an edge pulling but your smart too, dang I am defintly not looking forward to you repeatedly beating me. LOL Now just don't tell me you prepare taxes so i can have something on you.

[gambit]

I see where I was mistaken.

You have to only double one dimension, whether it be width or length, because if you double the slab only one of those will stay constant.

7 x 26 x 0.333 = 60.606 / 27 = 2.245 cu. yds

or

14 x 13 x 0.333 = 60.606 / 27 = 2.245 cu. yds


Thanks Gary !!

oh, and you too, JD...

[Gary Brown]

jdslough said:

I would say each slab individually. If you double then multiply again you will be way off, do each one as an individual, especially if you are pouring side by side

Gary, now not only do you have an edge pulling but your smart too, dang I am defintly not looking forward to you repeatedly beating me. LOL Now just don't tell me you prepare taxes so i can have something on you.

I don't prepare taxes so you are safe there. I would like to be able to figure my odds in and out of the strap. Thing is it constantly changes as I learn and as I move up to open classes. My first couple tournaments I could get just about any match in the straps and once I did i would win. Then it started to change that I needed to stay out of the strap. I think more experienced guys have a heck of alot more side pressure regardless or bicep strength. I know my odds going inside or outside.

I can tell you a little about how plastics flow, like how heat effects viscosity, degradation. Residence time and shear heat from screw recovery also comes into play. Newtonian and Non- newtonian flow. Amophous vs Cystalin. Resin addatives such as UV stabalizers and reinforcers such as fiberglass. Thermosets vs thermoplastics.

I know a little about strelization proceders and disinfecting, and some about pressurizing vessels and nitrogen. I know a little about supervision.

Back to math all I do is try to simplify problems by converting everything to 10s in my head and then work the smaller numbers and put it back together. That makes me good at decimals and percentages. I like Geometry and Trig and love maps. Unfortunatly I never get to use either in my work.

You guys have me wanting to do math exercises to brush up now.