Question 794738
This is a specific example of a general type of two-part mixture problem.  You can use all symbols first, as this:


L = lower priced
T = target priced
H = higher priced
M = amount of blend
u = how much of L
v = how much of H
The unknowns are u and v.


Note, {{{L<T<H}}}.


{{{(Lu+Hv)/M=T}}} and {{{u+v=M}}}.


Solve that as a system completely in symbols for u and v.
Substitute values and evaluate.