Note Book Summary (7. 2) Ratio: A ratio is a comparison of two numbers. You generally separate the two numbers in the ratio with a colon (: ).
Suppose you want to write the ratio of 8 and 12.
You can write this as 8: 12 or as a fraction 8/12, and we say the ratio is eight to twelve. Fraction: There are different ways of writing a fraction. For example, two fifths of an object can be written as: A common fraction A decimal 0. 4 A percentage 40% Decimals: A decimal is a proper fraction whose denominator is a power of 10. To convert a fraction into a decimal: Divide the denominator (the bottom part) into the numerator (the top part): ? = 1: 4. 00 = 0.
25 Percents: Percent is a ratio of a number to 100. A percent can be expressed using the percent symbol %. 10 percent or 10% are both the same, and stand for the ratio 10: 100. (7. 3) Percent of a Number: To find the percent of a number write the percent as a decimal and then multiply by the number. 45% of 200 = o.
45 x 200 = 90 (7. 5) Discount and Sale Price: A discount is a reduction in the cost of an item. The sale price of an item is its regular price minus the discount. Discount: 40% off a shirt at $49. 50 = 19. 8 Sale Price: 40% off a shirt at $49.
50 – $19. 80 = $29. 70 (7. 6) GST (7%) & PST (8%): The Goods and Services Tax (GST) is a federal government tax. The rate is the same for all provinces.
The Provincial Sales Tax (PST) is a rate determined by each province. In some provinces, the PST is calculated on the selling price only. In other provinces, the PST is calculated on the sum of the selling price and the Goods and Services Tax (GST).
Shoes: $170. 00 GST: $11. 90 PST: $13.
60 (7. 7) Commission: The commission on an item is the percent of the selling price that a salesperson earns when he or she sells the item. Selling Price: $9520 Commission rate = 7%Commission = 7% of $9520 = 0. 07 x $9520 = $666.
40 (7. 8) Finding the Percent of a Number: To find what percent one number is of another, write the numbers as a ratio, determine the decimal equivalent, and multiply by 100%. 20 is what percent of 60? 0. 3 x 100% = 30% (7. 11) Simple Interest: Interest in an amount paid on money borrowed or invested. The total of the principal and interest is called the amount.
The formula to calculate simple interest is (I = Prt), I = the Interest P = the Principal R = the Interest Rate T = the Time in Years Tania Chalhoub.