mathematical terms

Status
Not open for further replies.
R

rudy.v

Member
Location
Texas
ok, I am a little confused here, and I hope someone can clear it up for me. what is the difference when the following terms are used
" #1. shall not be less that 125%" and #2.not less than 125 %. I noticed term # 1 in section
210.20(a), and term # 2 in 422.13. these terms were on a test I took and on term # 1 it was a division math solution, whereas in # 2 the math solution was multiplication. What gives?
 
B

bennie

Esteemed Member
Re: mathematical terms

I just bought a book titled "Complete Idiot's Guide to Grammer and Style".

One of the major rules of grammer is "Don't use no double negatives" :(

This is an example of the poor writing style, some of us mentioned on another thread.

Not less than 125%, means more than, and including 125%.

Should this read...More than 125% of the ampacity it would not include 125%.

This is not really an answer to your question. Can you give more details of exact wording on the test?.
 
B

bphgravity

Senior Member
Location
Florida
Re: mathematical terms

Both phrasings are mathematicaly the same thing.

If the question gives you the equipment rating first, you must multiply by 125% to get the branch circuit rating.

(10-amp x 125% = 12.5-amp)

If the question gives the branch circuit rating first, you must divide by 125% to get the equipment rating.

(12.5-amp / 125% = 10-amp)

I do not see where your confusion is? :confused:
 
B

bennie

Esteemed Member
Re: mathematical terms

Bryan gives a good explanation. It all depends on the direction of calculation.

Remember...Double negatives are never not wrong :confused:
 
charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Re: mathematical terms

I agree with Bryan on the approach to this type of math problem. In the case of the two NEC sections you cited, both are written in the context of Bryan?s first example. Both give you the equipment rating, and ask for the branch circuit rating.

I also agree with Bennie, in that it ain?t but no good to avoid not using double negatives. I agree that the sections you cite (and many others) are poorly written. However, the phrase ?shall not be less than? contains no double negatives. The word ?not? negates the word it modifies. The phrase ?less than? quantifies, but does not negate, the word it modifies.
 
B

bennie

Esteemed Member
Re: mathematical terms

Yogi Berra was once asked " who is going to win the game" His answer "I don't think we won't win"

Did he write the code book ;)
 
physis

physis

Senior Member
Re: mathematical terms

#1 Can't.

#2 Isn't.

Is what I get from the way you posted the wording.

#1 Shall not be less than.

#2 Shall have a rating not less than.

Is what the corosponding codes say. Virtually synonymous.

I'm going to expand on what Bryan is saying. To me multiplying and dividing are the same thing. It's a matter of direction.

I did this recently but it's worth doing again.

2 x 3 = 6 is the same as

6 / 3 = 2 or

6 / 2 = 3

These are also synonyms.

Rudy, your doing fine, better than me. :cool:

[ May 17, 2003, 05:41 AM: Message edited by: physis ]
 
C

canman

Member
Re: mathematical terms

Rudy,could you have seen the use of a reciprocal?
30x1.25=37.5.If I had wanted I
could have done the same thing by division using the reciprocal of 1.25. 1/1.25 gives a reciprocal of .80. 30/.80=37.5.
 
Status
Not open for further replies.
Top