solver (LP) constraints

hi everyone... i have the following problem.

I have like 10-20 products.. you name it.

i want the solver to actually select the ones that min the cost to run them while be within a budget ($).

However, i also want them to be within a specific age band (ie the average of the ones the excel will select)...This.. i cannot do. don t understand why.
everywhere on the net i see the formula sumproduct() of use...but no reference to other excel formulas like if(), average(), etc...

is it not working because of this fact?


please help me...it will help me in my work

(the constraint to use is in yellow cell, ie i want the yellow cell to be...say within 5-11)