Percent Applications

Example: Lauren bought and planted two packages of flower seeds to use in her science fair project. Package A contained 44 seeds of which 32 grew into plants. Package B contained 36 seeds of which 27 grew into plants. Which package of seeds was better? Estimate, then calculate.

Estimate using benchmarks of ½ (50%) and ¼ (25%):Package A:32 out of 44 seeds grew.50% of 44 is half of 44.Half of 44 is 22.25% is half of 50%.Half of 22 is 11.50% + 25% = 75%22 + 11 = 33 A little less than 75% of the seeds from Package A grew.

Package B:27 out of 36 seeds grew.50% of 36 is half of 36.Half of 36 is 18.25% is half of 50%.Half of 18 is 9.50% + 25% = 75%18 + 9 = 27 Exactly 75% of the seedsfrom Package B grew.

Calculate: (to the nearest tenth)Package A:

% grown = 3244 x 100% = 72.7%

Package B:

% grown = 2736 x 100% = 75%

Package B was better than Package A.

Sale Prices & Shopping, Tipping at Restaurants, and Taxes

When shopping, it is often useful to be able to calculate a percent, to find the sale price, the final price, or to decide which of two offers is the better deal.

Sale Prices & ShoppingA pair of Converse shoes cost $129.00. They went on sale at 25% off. What is the sale price of the shoes before taxes?

Recall – “of” in math = multiply (x)25% of $129.00= 25% of $129.00= 0.25 x $129.00= $32.25 (this is the amount taken off the original price) New Price = $129.00 - $32.25 = $96.75 (before tax)

Another Method:If the shoes are 25% off, then that means you’re paying 75% of the original price:

New Price = 75% of $129.00 = 0.75 x $129.00 = $96.75

Tipping at a Restaurant

Gratuities are seldom included in Canadian restaurants. It is customary to tip approximately 15-20% on the total bill before tax, less for poor service, more for truly exceptional service. Many restaurants may charge an automatic 15-18% gratuity for larger groups.

The tip should be calculated on the SUBTOTAL (Before Taxes)

Example: Calculate an 18% tip for the following Crabapples restaurant bill:

Tip = 18% of $77.71= 0.18 x $77.71= $13.99

Total on Bill = $85.39 + $13.99= $99.38

Next time you’re out a restaurant with your family, try calculating the tax and total amounts!

Calculating TaxesTaxes are mainly used to finance the expenses incurred by government to manage an economy. These expenses may include: health care, education, garbage collection and operating government business entities, etc.

Currently, in BC we have two taxes: GST – Goods and Services Tax (5%) and PST - Provincial Sales Tax (7%)

Example: Alicia is planning a trip to Ambleside beach while visiting relatives in North Vancouver. She wishes to buy each item shown:

a) What is the total cost of the items before tax?Total cost = $21.87 + $5.49 + $11.99 = $39.35

b) What is the GST and PST on these items in British Columbia? What will be Alicia’s total bill?

GST = 5% of $39.35 = 0.05 x $39.35 = $1.97PST = 7% of $39.35 = 0.07 x $39.35 = $2.75Total Cost = $39.35 + $1.97 + $2.75 = $44.07