Re: Help With A Math Problem!

GrailSeeker · ‎12-01-2012

If

@Love my grandkids wrote:
I'm usually good at what I call "regular" math but never can figure out this kind of thing, never could in school either:

A merchant is offering something for $49 which is 75% off the regular price.

How do I figure out what the regular price is? Thanks!

We were taught to figure it out this way.

If $49 is 75% off, then $49 = 25% of the original price, which would be 100%.

$49 is to 25 (%) as $____ is to 100 (%).

Take the two numbers on the ends of the equation times each other and divide by the number in the middle of the equation.

49 x 100 = 4900. 4900 divided by 25 = 196.

Reverse the process if one of the end numbers of the equation is missing. Multiply by the two center numbers by each other and divide by the number on the end:

$____ is to 25% as $196 is to 100.

25 x196 =4900. 4900 divided by 100 = 49.

I can't remember when we were taught this, maybe 7th grade, but it has always stuck with me. Maybe pre-algebra, because we were trying to find an unknown number.

sunshine45 · ‎03-09-2010

@Jersey Born wrote:
@CLHS68 Is correct.

We know that if we take 100% of the price and subtract 75% from it, we will be left with 25% of the the full price.

$49 = 25% of the full price.

So, $49 = 1/4 of the full price, because 25%, or 25/100 can be reduced to 1/4.

You then set up an equation. 49 = 1 X is the number we want to determine.
X 4

Then, you cross multiply and get 1X = 49 times 4, or X = 196

So, the full price is $196.00.

@Jersey Born

good job......thanks for showing how you got there.

this is the way i learned it many years ago!

at least for math class.

********************************************
"The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing." - Albert Einstein

Jersey Born · ‎03-10-2010

@Susieq and @sunshine45 I wrote out my solution, because I wanted to help the original poster, using the method I was taught many years ago. Glad something stuck in my head from all those years ago!

Silver Lining · ‎04-16-2010

@GrailSeeker wrote:
If
@Love my grandkids wrote:
I'm usually good at what I call "regular" math but never can figure out this kind of thing, never could in school either:

A merchant is offering something for $49 which is 75% off the regular price.

How do I figure out what the regular price is? Thanks!
We were taught to figure it out this way.

If $49 is 75% off, then $49 = 25% of the original price, which would be 100%.

$49 is to 25 (%) as $____ is to 100 (%).

Take the two numbers on the ends of the equation times each other and divide by the number in the middle of the equation.

49 x 100 = 4900. 4900 divided by 25 = 196.

Reverse the process if one of the end numbers of the equation is missing. Multiply by the two center numbers by each other and divide by the number on the end:

$____ is to 25% as $196 is to 100.

25 x196 =4900. 4900 divided by 100 = 49.

I can't remember when we were taught this, maybe 7th grade, but it has always stuck with me. Maybe pre-algebra, because we were trying to find an unknown number.