[orelan]

Can someone help me with this problem? I'd be grateful.
The Everton College store paid 1532 for an order of 42 calculators. The store paid $8 ea. for science calculators. The others, all graphing calculators, cost the store $54 ea. How many of each type of calculators was ordered?
Thank-you for any help.

[Perito]

$1532 for 42 calculators

I assume that the store didn't mark up the price. Otherwise, the problem is unsolvable.

S = number of scientific calculators
G = number of graphing calculators

S + G = 42
8S + 54G = 1532

You now have two (independent) equations and two unknowns. That is easily solvable.

[Stratmando]

This is how you(I would) figure if you don't know the formula.
You know most of the $1532 will need to be eaten up with the $54 calculators. 1532/54=28.370370..
so their can't be more than 28 $54 calculators, so you try 25X54=1350, so you try 17(42-25)X
8 and that equals 136.
1350+136=1486.
Now you know it is between 26 and 28 $54calculators.
The real problem is showing how you got this answer.