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You can put this solution on YOUR website!
There is a jillion questions of this type - mark-up, mark-down, sale price, interest earned, etc etc.
\n" ); document.write( "Actually the process is straight forward. If, as in your case, it asks for mark-up the selling price will be HIGHER, so you ADD.
\n" ); document.write( "So your answer will be higher than $40. How much higher?
\n" ); document.write( "Here it is 40% higher. Forty percent of what?
\n" ); document.write( "Forty percent of their COST. What's their cost?
\n" ); document.write( "It is given as $40. How do you calculate 40% of $40?
\n" ); document.write( "40% of $40 means that you multiply the two numbers.
\n" ); document.write( "BUT if you do that you get $1600, which is obviously too much for running shoes! What did I do wrong? The problem is that, although used all the time, the percentage (%) can't be used in mathematical calculations. It MUST be converted to a unitless ratio by divide the given percentage number by 100.
\n" ); document.write( "40% becomes 40/100
\n" ); document.write( "Now multiply (40/100) by the cost of $40
\n" ); document.write( "Mark-up is = (40/100)*40 = 1600/100 = 16. Sixteen what? Since 40/100 has no units the product has units of dollars ($).
\n" ); document.write( "The mark-up is $16. Whats the selling price?
\n" ); document.write( "Selling price = store's cost + mark-up
\n" ); document.write( "Selling price = 40 + 16
\n" ); document.write( "Selling price = 56
\n" ); document.write( "Your answer: The store's selling price for the running shoes is $56.\r
\n" ); document.write( "\n" ); document.write( "Let's omit the tutorial and calculate the selling price, S.
\n" ); document.write( "1) S = 40 + (40/100)*40
\n" ); document.write( "2) S = 40 + 0.40*40
\n" ); document.write( "3) S = 40 + 16
\n" ); document.write( "4) S = 56
\n" ); document.write( "Selling price is $56
\n" ); document.write( "Agree? Sort of easy, but I have the DrBeeee short cut. After you do several hundred of such problems and watching a store clerk calculate the sales price, you recognize that steps 2) and 3) can be replaced with one step.
\n" ); document.write( "In step two above, note that 40 (the base cost) factors out of each term, and we can rewrite 2) as
\n" ); document.write( "2)' S = 40*(1 + 0.40) then 3) becomes
\n" ); document.write( "3)' S = 40*(1.40)
\n" ); document.write( "4) S = 56
\n" ); document.write( "This short cut avoids the addition of 16 to the cost of 40
\n" ); document.write( "Understand what I did? No, stick to the first set of step a few more times. Yes, you are an extremely good learner.
\n" ); document.write( "Further comments.
\n" ); document.write( "Many problems ask for the sales price on an item listed say at $39, with a discount of 20%. We do the same as above with the exception of a MINUS sign.
\n" ); document.write( "Sales price = List price - Discount
\n" ); document.write( "S = 39 - (20/100)*39
\n" ); document.write( "S = 39 - 0.2*39
\n" ); document.write( "S = 39 - 7.8
\n" ); document.write( "S = 31.20
\n" ); document.write( "Sales price is $31.20 Note: Always give monetary values to the nearest cent (or 1/100 decimal place).
\n" ); document.write( "If you performed the calculations with me, don't you find steps 2 and 3 a bit annoying? Try my short-cut
\n" ); document.write( "S = 39 - (20/100)*39
\n" ); document.write( "S = 39*(1 - 0.2)
\n" ); document.write( "S = 39*(0.8) Note: you don't have to subtract 7.8 from 39
\n" ); document.write( "S = 31.20
\n" ); document.write( "I tell my students to do 100 of this type of problem and rest assured they know how to do them. You can too! Good doing! \n" ); document.write( "