<PRE><B>Question 729345</B>
u = amount of low strength material, 400 gallons
v = amount of high strength material, unknown gallons
L = concentration (of money) of low strength material, $1.29/gallon
H = concentration (of money) of high strength material, $1.35/gallon
T = concentration (OF MONEY) of mixture, $1.31/gallon


EQUATION TO RELATE THE QUANTITIES
{{{highlight((uL+vH)/(u+v)=T)}}}
Solve for v, and then substitute values to evaluate the formula of v.
</PRE>