Calculating Percent Name: Lawrence Status: student Age: 11 Location: N/A Country: N/A Date: N/A Question: MY MOM IS ON MY CASE. SINCE HOLIDAY SEASON SHE IS ALWAYS ASKING ME WHAT THE PRICE OF SOMETHING IS WITH THE % DISCOUNT SIGN ON IT. HOW DO YOU DO DISCOUNT OR PERCENT OFF OF A PRICE? I DON'T WANT HER TO KNOW I DON'T REMEMBER SO A LOT OF TIMES I GO AWAY WHEN SHE IS NEAR THE RACK. Replies: It requires doing some math in your head. If the price says "\$Y," and the discount tag says "X % off," the discounted price is \$Y (1-X/100). In English, that means you multiply the percent off by the price, divide by 100, and subtract this from the original price. For example, if the price tag says \$24.95, and the sign says "10% off," 10 times 24.95 is 249.5. Divided by 100, that's 2.50 (rounded off), which you subtract from the original 24.95 to give approximately \$22.50 (ok, \$22.45, but the whole calculation is easier if you realize that \$24.95 is very close to \$25). Richard Barrans Jr., Ph.D. Chemical Separations Group Hello, A percentage simply means part per 100. So, one percentage of a hundred dollar is one dollar. Five percentage of a dollar is five cents. So, if a carton of milk is normally \$2.99 and it on sale for 10% discount, it means that you will take off 29.9 (actually 30) cents off the \$2.99. Your net cost will be \$2.69. When you get a discount of 10% it means that you pay only 90% of the regular cost. I hope this help. Good luck Dr. Ali Khounsary Advanced Photon Source Argonne National Laboratory ``Per cent'' is French (roughly) for ``out of each hundred''. So a discount of 30 per cent is a reduction in the price of 30 pennies out of each hundred. Get it? Suppose the original price is 20 dollars = 2,000 pennies and the discount is 30 per cent. There are 20 hundreds of pennies in 2,000 pennies. For each of these we get a break of 30 pennies, so we get a total break of 20 x 30 = 600 pennies, or 6 dollars. Hence the discounted price is 20 - 6 = 14 dollars. Grayce Lawrence, To do a quick calculation, subtract the discount percentage from 100, and use that number as a percentage multiplier to get the discounted price. For example: say there is an item for \$45.00, with a 15% discount. 100 minus 15 is 85. Your new price would be 85% of the old price, so you can multiply the old price by 0.85, which is 85 percent written in decimal form. 0.85 times \$45.00 is \$38.25; this is the discounted price. Thanks for using NEWTON, and many happy returns! Richard R. Rupnik Internal Quality Auditor Lucent Technologies Click here to return to the Mathematics Archives

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