Percentages

1 st Type FIND “some” % OF “something else” Remember “OF” means “multiply by” –Per cent means “per 1 hundred” so 35% of 200 means “35 out of a hundred” x 200, i.e. Three steps to work it out are: i. Write out question as e.g. 43% of 300; ii. Then as iii. Remember to check your Answer There are 3 Types of % questions

2 nd Type Express “one thing” AS A PERCENTAGE OF “another” Four steps to work it out are: i. Write fraction with smallest number on top; ii. Then write decimal, and iii.Multiply by 100 iv.Check your answer …continued - 3 Types of % questions 12  80 X 100

2 nd Type continued – Percentage Change This is still about determining the change in value as a percentage of “another value” and is therefore still Type 2 Not much to worry about here – just an equation which is illustrated below with an example …continued - 3 Types of % questions Percentage “Change” Percentage “Profit” With an example using profit

3 rd Type These are identified by them not giving you the Original Value If its increasing in value, e.g. “A house increases in value by 25% to £ Find its value before the rise”, then the steps are: i.Set the increased amount equal to (100 + the % increase); ii.Then divide through by new high value to find 1% iii.Multiply by 100 to get 100% iv.Check your answer – Does seem reasonable? …continued - 3 Types of % questions

3 rd Type continued If its decreasing in value, e.g. “A house decreases in value by 21% to £ Find its value before the rise”, then the steps are: i.Set the decreased amount equal to (100 - the % increase); ii.Then divide through by new low value to find 1% iii.Multiply by 100 to get 100% iv.Check your answer – Does seem reasonable? v.Don’t forget you can back calculate using (  ) x 100 which gives 79% or use the percentage change formula in Type 2 to see that it is a 21% fall in price. …continued - 3 Types of % questions

A shop has a sale – it starts Tues and finishes Saturday. Each day items fall by 15% of their previous day’s value. i.A coat starts on Mon at £19.95, what is it on Wednesday? ii.£19.95 x 0.85 = y iii.y x 0.85 = £14.41 …Sales type questions