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dddannie6
Course Students
 
Posts: 20
Joined: Mon May 07, 2012 12:36 pm
 

Canceling Out a number in the denominator

by dddannie6 Fri Jan 10, 2014 1:57 pm

Hi,

So I am working on a problem in the big book having to do with percents and fractions. One of the steps mentioned to simplify this:

(1/100) times (200/100) times 360 = (x/100) times (.1/100) times 60

was to multiply both sides by 10000 to cancel out the 100s in the denominator on each side. I understand the logic for this but what I don't understand is why this does not effect 360 or the 60 on either side equal sign. I would think that if you are multiplying both side by 10000 this would also include the 360 and the 60 as well.


-Dannialles
tommywallach
Manhattan Prep Staff
 
Posts: 1917
Joined: Thu Mar 31, 2011 11:18 am
 

Re: Canceling Out a number in the denominator

by tommywallach Sun Jan 12, 2014 2:10 pm

Hey DDD,

You're thinking of distributing with addition and subtraction. But you don't distribute with multiplication. For example:

If you have (x + 1) and you multiply it by 2, you get 2x + 2.

But if you have (2x) and you multiply it by 2, you just get 4x (i.e. you don't multiply both the 2 and the x by 2).

Make sense?

-t
dddannie6
Course Students
 
Posts: 20
Joined: Mon May 07, 2012 12:36 pm
 

Re: Canceling Out a number in the denominator

by dddannie6 Mon Jan 13, 2014 11:27 am

I see!

Thanks for your help!

-DDD
tommywallach
Manhattan Prep Staff
 
Posts: 1917
Joined: Thu Mar 31, 2011 11:18 am
 

Re: Canceling Out a number in the denominator

by tommywallach Wed Jan 15, 2014 3:32 pm

No problem!

-t