I have always been an idiot when it comes to math. If your in a store and something cost $25 and it is 30% off what is the cost of the item?? I have no idea how to figure this out. Help please!
2007-03-21 02:39:12 · 6 answers · asked by joyce 5 in Science & Mathematics ➔ Mathematics
The key is to remember that a percentage can be rewritten as a decimal. Just move the decimal point two places to the left (and get rid of the % sign) and you're set. For example, 30% becomes 0.3. In this case, if something is a certain percentage off, the remaining cost will be 100% minus the discount. So 30% off means a remaining cost of 70% of the original cost.
So to do this problem, consider the fact that the new cost is 70% of the original cost. 70% is 0.7. That means that the new cost is $25*0.7 = $17.50.
2007-03-21 02:45:35 · answer #1 · answered by DavidK93 7 · 0⤊ 0⤋
The easiest way to figure any percentage like you mentioned is to figure out what 10% of the total amount is. This can be done by moving the decimal point one position to the left. 10% of $25.00 is $2.50, 10% of $30 is $3.00, 10% of $46 is $4.60 and so on. So if you want to figure out what 30% of something is multipy the 10% by 3. 30% of $25 is $4.50, 30% of $30 is $9, 30% of $46 is $13.80. Just subtract the savings from the original price and you know how much you have to pay. In the example you gave the new amount would be $22.50 ($25 - $2.50).
Of course that requires you to remember the first answer, multipy it in your head without forgeting it and then arrive at the correct answer without forgetting to carry a number. If your out shopping the easiest thing to do is to carry a small pocket calculator with you to do the work for you or a small sheet of paper so you can to the math on it. If you use the calculator just multipy the number by the percentage. If the calculator won't let you do that then convert the percentage into decimal form by moving the decimal point two places to the left. 30% becomes .30. so in your example you would type in 25 x .3 to get you answer of how much you are saving.
2007-03-21 03:17:24 · answer #2 · answered by Doc E 5 · 0⤊ 0⤋
Percentage means you have to divide the number by 100, and the percentage value has to be multiplied with the total number to find the portion of the percentage value.
The total value is always equal to 100%
Therefore in this example, 100%=25
If there is a 30% off or reduction in price, the new price will be (100-30), or 70% of the original 100%price, which equals 70% of 25
=70/100*25
=$17.5
2007-03-21 02:54:57 · answer #3 · answered by Bubblez 3 · 0⤊ 0⤋
Discount = Original - (Percentage times original price)
D = original - (% * Original)
D = 25 - (30% of 25)
D = 25 - (30/100 x 25)
Simplifying:
D = 25 - (3/10 x 25)
D = (25 -7.5)$ = $ 17.50
Or:
(100 - 30)% = 70%
$ ............. %
25 ===> 100
d ====> 70
d = (70 x 25) x 100
d = $17,50
Answer: Original price: $ 25. Actual price $ 17.50.
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2007-03-21 03:19:16 · answer #4 · answered by aeiou 7 · 0⤊ 0⤋
a guide to percentages is that always treat it as a fraction of a total amount MULTIPLIED by 100
30% of a dollar for example is = 30/100x $1
use the same concept to find the solution to your problem--> cost of item=70%
= 70/100 x $25 = $17.50
2007-03-21 02:50:02 · answer #5 · answered by llcold 2 · 1⤊ 0⤋
to work out a percentage first you convert it to a decimal.
Therefore in this case, we want 30% so we simply divide by 100% (the total).
30 / 100 = 0.3 (30% as a decimal)
Now we multiply this value by the original price.
$25 x 0.3 = 7.50 (this is how much we will save)
Now we subtract this from the original price....
25 - 7.50 = $17.50
2007-03-21 02:46:00 · answer #6 · answered by Doctor Q 6 · 0⤊ 0⤋