Linear Equations

Question

Lilia is interested in buying a laptop computer. She has a coupon for 25% off one item. There is a
6% sales tax on the computer. The final price of the computer after the discount and tax is $357.75.
What is the original price of the computer?

Answer 1

Let x = original price of the computer.

 

The sale price is:   x - 0.25x             [note: 25% may be 25/100 or 0.25 as needed by the problem.]

 

Tax is on the sale price:

                sale price   +     tax                =  $375.75

                (x - 0.25x) + (x - 0.25x)*0.06 = $375.75

                0.75x*1.06  = $375.75        [note: some people would start with 0.75 and 1.06]

               7950x = $3757500          [get rid of decimals by multiplying by 10000]

                   x = $472.64

 

Check:

      original price   =   $472.64

   25% of $472.64  =    118.16

      sales price       =    354.48

         tax                 =      21.27

      final price        =   $357.75     Check!