Percentage

• Percentages are special types of fractions in which the denominator is always hundred.
• To convert a ratio into a percent, we first write it as a fraction and multiply it by 100 and put a % sign. To convert a percent into fraction, remove the % sign, divide by 100 and reduce the fraction to lowest terms.
• To convert a decimal into a percent, we shift the decimal two places right and add a % sign. To convert a percent into a decimal, remove the % sign and shift the decimal two places to left.
• Percentage increase/decrease is given by
              (change / original value) × 100%

Exercise

1. What percent of a day is half an hour?
2. A lunch interval of half an hour is 5% of total office hours. Calculate the total working hours.
3. In a students election, Rahul got 66% of the votes polled. If he got 363 votes, find the total number of voters.
4. Prices of bananas has changed from 5 for a rupee to 4 for a rupee. Find the percentage increase in price.
5. Sandys height increased by 20% last year and by 15% this year. What is the total percent increase in 2 years?
6. Price of a commodity decreased by 10% last year and increased by 20% this year. Find the %age change in price in two years.
7. In a class, section A has 42 boys out of total 75 students, section B has 60% girls in a total student strength of 80 and section C has two third boys among 45 students. Find the aggregate percentage of boys.

Answers