trying to find percent of change original is 35, new is 40 i got 35-40/40=r/100

Question

trying to find percent of change original is 35, new is 40       i got 35-40/40=r/100

anonymous · Answer

100 x (new - original) / original

anonymous · Answer

but its  
$$\frac{ r }{ 100 }$$

anonymous · Answer

Where is this "r" coming from?

anonymous · Answer

the r is the percent out of 100 im trying to find

anonymous · Answer

|dw:1352163713553:dw|

anonymous · Answer

ok, my equation still holds and gives you your "r" and you can think of it as r/100 which is a fraction and that's all good, but you don't want 40 in the denominator because you are comparing off of the original, not the changed value.  All I did was move the 100 over to the other side.  But change that denominator as directed.

anonymous · Answer

so what youre saying is to change 40 to 100? and do the same type of thing to the numerator?

anonymous · Answer

change 40 to 35, the original value

anonymous · Answer

how do i do that? sorry i really suck at this

anonymous · Answer

(new - original) / original = r/100    Where new is 40 and original is 35.

anonymous · Answer

well i have |dw:1352164370260:dw|

anonymous · Answer

for some reason im leaning towards the equation 40r=-5*100

anonymous · Answer

(new - original) / original = r/100    Where new is 40 and original is 35.  This gives (40 - 35) / 35 = r/100.  You have to have 35 in the denominator, not 40.

anonymous · Answer

oooooooh ok i see what i did wrong. it should be|dw:1352164636060:dw|

anonymous · Answer

so 5/35=r/100

anonymous · Answer

Yes!  The "35" in the denominator is required because it is a comparison off of the original.  You are basically using change / original.  Computer is messing with my keyboard.

anonymous · Answer

ha okay so to solve for r i do 35r=500?

anonymous · Answer

Yes!  You are getting it now!  Good job!

anonymous · Answer

500/35= 14.28571...

anonymous · Answer

Very good, my friend!

anonymous · Answer

do i round it down? or does it stay as is?

anonymous · Answer

You will have to round it to some place because it will go on forever. 14.29 looks good.

anonymous · Answer

okay ha. and thank you so much! my math teacher talks really fast and doesnt explain anything very well...

anonymous · Answer

You're quite welcome!  And watch out for those fast-talking math teachers!

anonymous · Answer

yeah ha he always loses me when talking about fraction related things