Percents

Help with Percents

• Calculator Method--caution will not work on all percent problem.
• Sample: A tire costs $120.  The dealer has a special on tires with a 30% discount.  What is the cost of the tire with the discount?
  • Put 120 in your calculator.
  • Put a (- )sign in your calculator. (this is a discount therefore the price will be less.
  • then place 30 in the calculator
  • Then the % sign.  This will give you your answer.  ( $84 ) This system will work on the FCAT calculator -- not on all calculators.

   

• When the question asks for a percent  (little number divided by big number) 
  • Sample:  The dealer took $20 off the price of $120 item.  What is the percent of discount. 
    •   20   Little   
    • 120   Big
    • .1666    or 16%
  • Caution:  When using this method make certain The little number is what the problem is asking for.  
    • Sample:   An item originally sold for $120 .  It was offered on a sale for $100.  What was the percent of decrease? 
      • 120 - 100 = 20  this is my small number it also represents the decrease.

       

• When a percent problem asks for an amount in the past this is an algebra word problem
  • Sample:  A bicycle store owner sells all merchandise at 25% above original cost. A customer bought a bicycle for $140.00.   How many dollars did the store owner originally pay for the bicycle?
  • Let x = original price
  • Let .25x = amount of profit  --- difference between original and selling price
  • Make and equation        Original price  +  profit  is the selling price
  •                                                         x             +    .25x    =         140
  • Solve Equation                       1.25x   =    140     1.25x   =    140
  •                                                                                    1.25            1.25
  •                                                            x  =  112