Posted by spirit73 on .
the everton college store paid $1553 for an order of 42 calculators. the store paid $9 for each scientific calculator. the others, all graphing calculators, cost the store $56 each. how many of each trupe of calculator was ordered?
the store ordered:
how many scientfic calculators?
graphing calculators?

algebra 1 
MathMate,
Let
S = number of scientific calculators
"an order of 42 calculators."
42S = number of graphing calculators.
"the store paid $9 for each scientific calculator... graphing calculators, cost the store $56 each"
Total cost
= $9*S + $56*(42S)
Since the total cost is $1553, solve for S in
$1553 = $9*S + $56*(42S)