You probably put the amount (18) over 100 in the proportion, rather than the percent (125).
Perhaps you thought 18 was the percent and 125 was the base.
Jeff has a coupon at the Guitar Store for 15% off any purchase of $100 or more.
He wants to buy a used guitar that has a price tag of $220 on it.
A shop is offering discounts on shirts costing $20 each.
If someone buys 2 shirts, he will be offered a discount of 15% on the first shirt and another 10% discount on the reduced price for the second shirt. So they are easier to compare than fractions, as they always have the same denominator, 100. The amount saved is always the same portion or fraction of the price, but a higher price means more money is taken off.Interest rates on a saving account work in the same way.Example 47% of the students in a class of 34 students has glasses or contacts.How many students in the class have either glasses or contacts?Look at the pairs of multiplication and division facts below, and look for a pattern in each row.Percent problems can also be solved by writing a proportion.Since we have a percent of change that is bigger than 1 we know that we have an increase.To find out how big of an increase we've got we subtract 1 from 1.6.$$\frac=\frac$$ $$\frac\cdot =\frac\cdot b$$ $$a=\frac\cdot b$$ x/100 is called the rate.$$a=r\cdot b\Rightarrow Percent=Rate\cdot Base$$ Where the base is the original value and the percentage is the new value.