#21
11-15-2013, 01:05 PM
 Victorsaur LawnSite Member Join Date: Feb 2011 Location: Asheville, NC Posts: 78
It baffles me at times how confusingly the simple of math landscaping is presented. It seems like things are every which way and there is always something that one might have "missed". This is of course nonsensical as mathematical equations of this industry are very simple. The hard part is oftentimes obtaining the correct facts. You can't have an equation without accurate data.

With math if you're ever confused all you have to do it set up an equation. Since 60% WDG (a type of active ingredient or AI) is 60 AI you have a ratio of active ingredient to total stuff sprayed. Since 6/10 of your spray is AI and you want to spray a total of 2 pounds of it by finding X (the amount of total stuff to spray) your formula looks like this: 2/X = 6/10 since they are both ratios. Multiply each side by X and 10 and the equation becomes 20 = 6X. Divide each side by 6 to find X. Middle school math (not to be condescending)
#22
11-15-2013, 02:12 PM
 lilmarvin4064 LawnSite Senior Member Join Date: May 2005 Location: transition-zone Posts: 746
If you have one bucket that holds 2 gallons and one bucket that holds 7 gallons, how many buckets do you have ?

When I see the original question, to me, it sounds like this...

You need to apply 100 lbs of 10-10-10 fertilizer to a lawn. How many pounds of fertilizer do you need?

um.... let's see, 100 lbs.

I sure hope they would use the word "active ingredient" instead of herbicide in the first sentence, otherwise it may be confusing, or just a stupid question.
#23
11-15-2013, 09:41 PM
 CL&T LawnSite Senior Member Join Date: May 2011 Location: New York Posts: 491
Quote:
 I sure hope they would use the word "active ingredient" instead of herbicide in the first sentence, otherwise it may be confusing, or just a stupid question.
They do that to try and trip you up. You should know that the herbicide is the AI.
#24
11-16-2013, 07:26 AM
 wildstarblazer LawnSite Senior Member Join Date: Nov 2007 Location: South Georgia Posts: 760
I hate tests that make you think. We all know that you should not cut more than a 3rd of the grass blade when cutting grass. Okay, so instead of asking how much of the blade should be cut when cutting grass, they ask "If your grass is 3 1/2 inches long, what should be the final size of the blade after cutting?" Ya know? Camon, why make us think.
#25
11-16-2013, 10:15 AM
 Ric LawnSite Fanatic Join Date: Sep 2001 Location: S W Florida Posts: 11,353
Quote:
 Originally Posted by RigglePLC Or maybe, Water Dispersable Granule. WDG. That is a small granule that is not dusty, easy to pour, but disperses when added to water to form a suspension of powder in water. This is a common formulation for fungicides, insecticides and some herbicides. It is sometimes called a DG formulation. Skip is right. Normally, if the label says 2 lbs it will specify that the amount covers one acre. Add it to whatever amount of water your equipment applies to one acre. 60 WDG would normally mean a WDG formulation containing 60 percent active ingredient. If you need to calculate the rate on an AI, "Active Ingredient" basis...adding 2 lbs active ingredient, divide by the active ingredient, which is .60, so...2lbs/.6= the result would be 3.33 pounds. Question does not mention if it is to be applied on an "Active Ingredient" bases or the usual straight from the bag on an as formulated basis. The question said "site", it leaves out how many acres you will cover, and how many gallons per acre your equipment applies. Also how big is the tank?

I think it would be a little hard to end up with 3.33 Lb of active if you only started with 2 lb of product.

Quote:
 Originally Posted by Victorsaur It baffles me at times how confusingly the simple of math landscaping is presented. It seems like things are every which way and there is always something that one might have "missed". This is of course nonsensical as mathematical equations of this industry are very simple. The hard part is oftentimes obtaining the correct facts. You can't have an equation without accurate data. With math if you're ever confused all you have to do it set up an equation. Since 60% WDG (a type of active ingredient or AI) is 60 AI you have a ratio of active ingredient to total stuff sprayed. Since 6/10 of your spray is AI and you want to spray a total of 2 pounds of it by finding X (the amount of total stuff to spray) your formula looks like this: 2/X = 6/10 since they are both ratios. Multiply each side by X and 10 and the equation becomes 20 = 6X. Divide each side by 6 to find X. Middle school math (not to be condescending)
I taught Material Calculation & Calibration at a local State College. Middle school math is all material calculation are. 7th & 8th grade word problems that preceded Algebra 1. I was totally surprise at the lack of math skills of College students. How ever I was teaching a night school class to yard boys, who don't exactly win scholarships.

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#26
11-17-2013, 02:22 AM
 Victorsaur LawnSite Member Join Date: Feb 2011 Location: Asheville, NC Posts: 78
Quote:
 Originally Posted by Ric I taught Material Calculation & Calibration at a local State College. Middle school math is all material calculation are. 7th & 8th grade word problems that preceded Algebra 1. I was totally surprise at the lack of math skills of College students. How ever I was teaching a night school class to yard boys, who don't exactly win scholarships.
And can you blame them? Most of the time what is really simple is presented in a way that is really confusing and wastes a lot of time. For example, the math behind phosphorous fertilizer required to achieve a target saturation percentage given numbers drawn from soil tests. Yes, complications arise including soil type, CEC, etc, but what about a conclusive base formula with alterations to the base given these factors?

The reason why this industry is so confusing is that many times nothing is conclusive. Even if a conclusion is variable it is still a conclusion, and it is progress. Without this type of progress there is no systemic process for landscape professionals to do what should be easy.
#27
11-17-2013, 11:24 AM
 agrostis LawnSite Bronze Member Join Date: Nov 2009 Location: Winston-Salem NC Posts: 1,740
I highly recommend this book. If you shop around you can find a copy for \$25 or less.
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