Use percentage strips, each divided into ten equal sections (10% each), to solve the following problems. In some cases splitting 10% into two 5% sections might be helpful.
1) 30% of a number is the same as 15% of 40. What is this number?
| 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% |
| 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
10% of 40 is 4, so 15% is 6.
| 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% |
| 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
6 is thirty percent of another number. Each 10% us equal to 2. Therefore, 100% of the number is 20.
Solution: The number is 20.
2) What percent of 35 is the same value as 10% of 70?
| 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% |
| 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 | 7 |
10% of 70 is 7.
| 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% |
| 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 |
3.5 + 3.5 =7. Therefore, 20% of 35 is 7.
Solution: The percent is 20.
3) 25% of 96 is the same as 15% of what number?
| 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% |
| 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 |
10% of 96 is 9.6. 20% is 19.2 . Therefore, 25% is 24.
| 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% | 10% |
| 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 | 16 |
15% is 10% + 5% ⇒ 16 + 8 = 24. Therefore, each 10% is 16.
Solution: The number is 160.
Go back to Try This! (Solve Problems using Percentage Strips)
