Corey spent 25% of his savings on a printer at Louie's Electronics.

How much did Corey have in his savings account before he bought the printer?

Let c represent the original amount that this guy had saved up.

He spent 25% of this amount, or 0.25c, on the printer.

To progress further, we have to know how much the printer cost.

Supposing that the printer cost $100 (which we do not know as a fact), this would be equal to 0.25c.

Thus, his savings originally amounted to c = $100/0.25 = $400.