Question 305557
<font face="Garamond" size="+2">


Let *[tex \Large x] represent the number of gallons of 3% solution.  Then the gallons of pure salt in the 3% solution must be *[tex \Large 0.03x].  The number of gallons of 7% solution, given that we need 100 gallons overall, must be *[tex \Large 100\ -\ x], and the number of gallons of pure salt in the 7% solution must be *[tex \Large 0.07(100\ -\ x)].  And finally, there has to be 5 gallons of pure salt in 100 gallons of 5% solution.


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 0.03x\ +\ 0.07(100\ -\ x)\ =\ 5]


If you multiply by 100 you get integer coefficients -- much neater:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 3x\ +\ 7(100\ -\ x)\ =\ 500]


Just solve for *[tex \Large x].



John
*[tex \LARGE e^{i\pi} + 1 = 0]
</font>