The original price of a conputer is $1,250. At a year-end sale, the selling price of the computer was $900. Find the percent discount.

Question

Well i need help with finding the percent discount of the two numbers and its really confusing. I dont know what to do so im getting really confused on my question

Answer 1

The percent discounted is the difference between the original price and the sale price:

 

100% - (900 / 1250)% = percent discounted

⇒ 100% - 0.72 = 100% - 72% = 28%

 

Thus, the computer was discounted 28%

 

Another way is to find out how must it sold for:

900 / 1250 = 0.72 = 72%

 

Since it sold for 72% of the original price, then it must have been discounted 28%.

 

This second method basically breaks up the first method into two parts. Whichever is easier for you.

Answer 2

I recommend you use an algebraic ratio to solve problems using percentages.

 

 

Since percentages are based on a scale of 0 to 100 or the decimal values of 0 to 1 you can always represent them like this:

 

percent / 100

 

Since in your problem the percent is unknown and we wish to find it we should represent it as x, an unknown variable.

 

We know the value of the computer is 1250, which is it's full (100%) value. The decimal value of 100% is 1, but let's show this value as a fraction. Since the value of the computer is 1250 we can display it as:

 

1250 / 1250  This is read as 1250 dollars out of 1250 dollars.

 

The sale value of the computer is 900 dollars as stated in the problem. Written as a fraction this value is:

 

900 / 1250  This is read as 900 dollars out of 1250 dollars.

 

In word problems, the key word discount always represents a subtraction of value. In this case we want to know the actual value of the discount.

 

We now have enough information to set up our equation:

 

(1250/1250) - (900/1250) = x/100

 

First we need to simplify the left side of the equation, the rules for subtracting fractions are that the bottom half of the fraction, what is known as the denominator must be equal to each other, which is already the case here. Then you need to subtract the top parts of the fractions, what is known as the numerator, just as if the bottom part wasn't even there. 1250 - 900 is 350, therefore:

 

350/1250 = x/100

 

This is the standard form of a percentage ratio, it takes the form of:

 

value/total value = percent/100  This is read as the value out of the total value is equal to the percent out of 100.

 

The simplest way to solve this equation is through a process called cross-multiplication. The value is multiplied by 100 and the total value is multiplied by the percent. So then:

 

350*100 = 1250*x which is 35,000 = 1250x

 

You now solve this just like any other basic algebra problem, in this case divide both sides by 1250 and you are left with the percent discount:

 

35,000 / 1250 = x

 

So then:

 

x = 28

 

28% discount

 

I hope this helps you visualize this kind of problem in the future.

 

-Nick

 

Answer 3

Always figure the % discount from the original price. 

1250 - 900 = 350 << this is how much $ is subtracted to reach the new price. This is the discount. 

 

350 is what percent of 1250? 

 

1250(P) = 350 

 

350/1250 = 0.28

 

discount is 28%