Question 731340
ASSIGN VARIABLES
L=4.30 dollars per pound, type A
H=5.40 dollars per pound, type B
C=825.90 dollars cost of blend typeA+typeB
u=unknown pounds of type A
v=unknown pounds of type B
M=167 pounds blend typeA+typeB


MAKE SYSTEM OF EQUATIONS
{{{Lu+Hv=C}}}
{{{u+v=M}}}


SOLVE FOR UNKNOWN VARIABLES
Easiest may be use the material sum equation to get a formula for either u or v and substitute this expression into the cost equation and solve for the other variable; and then use the resulting formula in the material sum equation again to solve for a formula for the first variable.  The system is already two equations with two unknowns, and these equations are linear.

Since we are asked to find how much of type A coffee, ...
{{{u+v=M}}}
{{{v=M-u}}}, and then
{{{Lu+H*(M-u)=C}}}
You continue from here.


COMPUTE VALUES FOR UNKNONWS
Substitute the values to find the values for u and v.