Comparing Different Products (SQA National 5 Applications of Mathematics): Revision Note

Comparing different products

How do I find the best deal when comparing products?

• The best deal is the one with the cheapest price

• You need to find the total price of all the deals

How many deals do I need to compare?

• There will be at least three deals

• The price of one of the deals is normally given or straightforward to calculate

  • You might be given the total price

  • Or you might need to add the items together

• The price of a second deal normally involves getting some of the items for free or at a reduced price

  • e.g. buy 2 items and get 1 free

  • e.g. buy 3 items and get a fourth at half price

• The price of a third deal normally involves a discount on the overall price

  • It could involve percentages

    • There might be 30% discount

  • It could involve fractions

    • There might be a off the total price

How do I deal with buy-one-get-one-free deals?

• Calculate how many items you get using that deal

  • e.g. buy 2 and get 1 free gives you 3 items

  • e.g. buy 3 and get a fourth at half price gives 4 items

• Calculate the price of the deal

  • e.g. add together the price of the items you need to pay for

    • You might have to add one at half price or at another reduced price

• Calculate how many times you need to use the deal to get the required number of items

  • e.g. consider that you need 15 items using a buy-two-get-one-free deal

    • 15 ÷ 3 = 5

    • You need to use the deal 5 times

• Calculate the total price of using the deal to buy the required number of items

  • Multiply the price of the deal by the number of times you need to use the deal