A store sells two brands of calculators. The store pays $6 for each Brand A calculator and $8 for each Brand B calculator. The weekly demand for Brand A and Brand B calculators are x = 116 -30p + 20q...

A store sells two brands of calculators. The store pays $6 for each Brand A calculator and $8 for each Brand B calculator. The weekly demand for Brand A and Brand B calculators are
x = 116 -30p + 20q  and
y = 144 + 16p -24 q,
respectively, where
p
is the price per unit of Brand A and
q
is the price per unit of Brand B.

a) Determine the demand for each calculator when
p
= $10 and
q
= $12.

b) Express the weekly profit as a function of
p
and
q.