John invested part of his $6000 savings in common stock and rest in rare stamps. At the end of the year , she realized a gain of 9% on the stock and 12% on the stamps. If his savings now amount to $6615, hoq much did ge invest in stamps

Question

anonymous · Answer

Without figuring the amounts yet and just using a variable like "x", can you write an expression for how much was invested in common stock and then how much was used for the gain on stamps?  This is to get you started and the question is designed for you to get yourself started.

anonymous · Answer

I didn't get it

anonymous · Answer

If you have a fixed quantity of something to start with and you take away a variable or unknown amount, how much is the unknown amount taken away and what is the amount left?

anonymous · Answer

This should get you started.  How much do you have to start with?

anonymous · Answer

$6000

anonymous · Answer

If you are taking away a variable or unknown amount, how much are you taking away?  Hint: use a variable, like a letter.

anonymous · Answer

x+y=6000?

anonymous · Answer

That would be true, but this problem uses only one variable.  If you take away "x" amount of money for use as an investment vehicle for stamps, then you have "6000 - x" left for use in your investment in stock because:

x + (6000 - x) = 6000

No need to introduce a second variable.

anonymous · Answer

But x+(6000-x)=6000 is equal to 0

anonymous · Answer

No, what you have is:

6000 = 6000

You already have your equal sign.  You already have an equation.

You will have 615 in profit because you end up with 6615 at the end, so your interest profit is 615:

(0.12)(x) + (6000 - x)(0.09) = 615

So, now just solve for "x".

anonymous · Answer

X=2500?

anonymous · Answer

Is that right? 2500?

anonymous · Answer

Yes!  Good job!  So, 2500 is used for his stamp investment and the rest is used for stock.

anonymous · Answer

Thanks!

anonymous · Answer

More importantly, do you understand now how to set up the equation?  That's where the real work is.

anonymous · Answer

And you're welcome.  Nice working with you.

anonymous · Answer

Yes i know now, thank you !

anonymous · Answer

Good luck to you in all of your studies and thx for the recognition! @Kittykatkat14