Word problem method needed
Hi, I am looking for a method similar to age problems or rate, dist problems for getting a proportion of a mixture.
In this example I have to mix coffee1 at $6.50/unit with cofee2 at $9.00/unit to give me $7.50/unit.
I got the answer by doing it this way;
(6.50 + 9.00 )/7.5 = x
6.5/x + 9/x = 7.5
So 6.5/x is my coffee1 component.
Is this a accepted method or how would a diagram be used here? Anything that would make life easier will be good and will help remember what to do next time.
Thanks for the help.
Re: Word problem method needed
Quote:
Originally Posted by
SVDM 
(6.50 + 9.00 )/7.5 = x
Ehh, I don't think that works. That equation yields x = 2.066..., but we don't want x (also, what does x represent?).
A better way to solve it is let a and b be the number of units of coffee1 and coffee2, respectively. We take a weighted average:
For the LHS, the numerator represents the total cost of the coffee, the denominator represents the total # of units.
. That means, for every 1 unit of b (coffee2), we need 1.5 units of a (coffee1) to stay at $7.50 a unit. We like integer ratios so I'll multiply by 2, for every 3 units of coffee1 we need 2 units of coffee2.
