x = amount of seeds.
y = amount of dried fruits.
we know the snack mix contains both, and we know is 10oz, thus x + y = 10, whatever ounces "x" and "y" are.
how much is it for "x" ounces if each one costs $1.5? well is just 1.5*x or 1.5x.
how much is it for "y" ounces if each one costs $2.5? well is just 2.5*x or 2.5x.
the mix contains 10 ounces, each of which costs $2.2 each, how much will it be then for 10 oz? well, is just 10 * 2.2, or $22.
since the whole 10 oz snack mix costs 22 bucks, then 1.5x + 2.5y = 22.
[tex]\bf \begin{cases}
x+y=10\implies \boxed{y}=10-x\\
1.5x+2.5y=22\\
-------------\\
1.5x+2.5\left( \boxed{10-x} \right)=22
\end{cases}
\\\\\\
1.5x+25-2.5x=22\implies -x+25=22\implies 3=x[/tex]
how many ounces of dried fruit is there anyway? well, y = 10 - x.