Percent Problems
7-6Percent Problems
Overview
Use ‘percent · base = amount,’ or set up a proportion: part/whole = percent/100.
Key ideas
- Translate ‘is’ → =, ‘of’ → ×.
- Identify the base (the ‘whole’).
- Convert percent to decimal before computing.
Worked examples
Example 1
Problem. What is 30% of 80?
Solution. 0.30 · 80 = 24
Example 2
Problem. 12 is what percent of 50?
Solution. 12/50 = 0.24 = 24%
Practice
Try each one. Click Show answer when ready.
- 1.
What is 15% of 200?
- 2.
9 is what percent of 36?
- 3.
20% of what number is 12?
Challenge problems
A little tougher — great for test prep. Click Show answer when ready.
- 1.
A jacket is marked down 25% to $60. What was the original price?
- 2.
A salary increases from $48,000 to $51,600. What is the percent increase?