Math Is Fun Forum

jxharmon

Member

Registered: 2007-01-08

Posts: 104

Business & Finance ?

The revenue for a sandwich shop is directly proportional to its advertising budget. When the owner spent $2000 a month on advertising, the revenue was $120,000. If the revenue is now $180,000, how much is the owner spending on advertising?

I am not sure how to even start this???

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Business & Finance ?

Revenue means amount of total sales.
Advertising is amount of money to inform others of your business.
Directly proportional is harder to explain, and this is where you need help, I think.
If something is directly proportional to something else, then
first of all, this means if one thing is zero, then the other thing is zero.
So rule number one is That if Money In is zero, then Money Out is zero.
"Directly proportional" is not true for converting between Celcius and Farenheit.
Do you know why?  Because when Celcius is zero, then Farenheit is not zero, it is 32.
Now there is MORE you need to know about directly proportional.
And that is that when the money doubles, then the money out doubles.
And when the MoneyIntoAds triples, then the moneyOutToSales triples.
Now you understand the basics of the word "directly proportional".

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igloo myrtilles fourmis

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Business & Finance ?

Next, we have to do some examples to help you get started on this problem.
If I spend $10 on advertising, and I sell $100 worth of things because of that.
Now you know that whatever you spend, you sell ten times more than your Ad.
It doesn't really happen exactly like this in real life, but this is just pretend.
So now if you spend $5 on Ads, then you would sell $50 worth of things.
This example is easy because the number ten is used, and half, very simple example.

Now if the numbers are weirder, like your problem with the 2000 and 180000 and 120000, then
you have to get a little wiser to do the problem.
You have to figure out what you have to multiply 2000 dollars by to get 120000 dollars.
Then you have to take the bigger number 180000 dollars and divide it by the same multiplying number you found to get the answer.

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igloo myrtilles fourmis

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Business & Finance ?

Here's a simple example.
When you buy gum balls, the number of gumballs you get is
directly proportional to how many times you put coins in, and turn the crank,
and put your open hand under the door to get your gumballs.
So if you put one coin in the gumball machine and turn the crank, then you
get one gumball out.
If you repeat this over and over, then you get more gumballs.
Your inheritance of gumballs is directly proportional to your cranking efforts.

Lets say you found a gumball machine that gave you lots of gumballs everytime you
cranked the crank, but always the same number. 
The number of gumballs you get is directly proportional to the number times you
complete the cranking process.

For example, if you operate the gumball machine once, and you get nine gumballs.
Then if you operate the gumball machine twice, then you get eighteen gumballs.
It's like your problem.
If you put 2 thousand into Ads, you sell 120 thousand.
If you put in 4 thousand into Ads, you sell 240 thousand.
If you put in 8 thousand into Ads, you sell 480 thousand.
If you put in 1 thousand into Ads, you sell 60 thousand.
If you put in 2 thousand into Ads, you sell 120 thousand.
Make sense?
Good Luck !!!!

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igloo myrtilles fourmis