Quandaries and Queries
 

 

Parent of secondary child.

Question:

Assume 120 less 12% = 105.6, ie 120 minus a 12% discount is 105.6.

If I know that 105.6 is a discount of 12% from x, how do I find x??

Help please!!!!

David

 

 

Hi David,

I would first write a mathematical sentence (equation) that describes the statement

"120 minus a 12% discount is 105.6."

A 12% discount in $120 is 12% of 120 and 12% of 120 is 12/100 120 = 0.12 120. Thus the equation is

120 - 0.12 120 = 105.6

In the situation you describe you know the discount rate is 12% and you know the discounted price is $105.60, but you don't know the original price of $120. You call the original price $x so in this case the equation is

x - 0.12 x = 105.6

Thus

0.88 x = 105.6

Divide both sides by 0.88 to get

x105.6/0.88 = 120

Penny

 
 

Go to Math Central