A percent is a number that represents the fractional part out of 100 (per cent literally means per one hundred). Thus 94% means . Likewise we can represent a denominator of 100 with decimals by moving the decimal point by 2 places. So . Thus . The main aim of this wiki is to discuss about percentages.
The simplest way to perform arithmetic with percentages is to convert them to their decimal equivalent by moving the decimal two places, then adding the decimals.
If John has of the apples and Sally has , what percentage of the apples do they have if they combine their apple piles?
Converting the percentages to decimal and adding, we see that . Thus the answer is .
John and Mac were friends. In the election of the class monitor John secured of the votes and Mac secured votes. Being friends, they decided to combine their votes and mind the class together. If the total votes polled were , what is the total number of votes they jointly secured?
John has of of of bananas. How many bananas does John have?
Given two values of some variable taken at different points of time, percentage change measures the proportion of the difference between the two values to the original reading of . If the value of is positive, we call it a percentage increase; if negative, then decrease.
The general formula for percentage change is
The price of a commodity changed from to . Find the percentage change in price of the commodity.
Imagine a city with 10000 people at the beginning of a year. Given that the population at the end of that year is 10500, compute the percentage change of the population.
Let us assign symbols to the population readings:
We apply the formula for pecentage change:
We say that the percentage change of the population from the beginning to the end of the year is an increase of . This means that population grew 5% in proportion to the initial count.
The price of a commodity is . If its price increases by %, then what is the new price?
Let's take our knowledge of percentages to a whole new level by practicing word problems on them. Some examples are given below.
Of students of the school, attempted the examination, of which failed. How many students passed the examination?
Of all the students enrolled at BRCM Public School, are in the band. The band has members. How many students are enrolled at the school?
We know that the band members are equal to of the total population of the school. We need to find out the total number of students that go to BRCM.
We can first divide by to see that students equal , then multiply by to see how many students equal :
Therefore, there are students at the school.
In Idaho, there are 23 Democratic delegates, to be proportionally distributed to Bernie Sanders and Hillary Clinton based on the popular vote. Bernie Sanders gets 78.8% of the vote. Hillary Clinton gets 21.2% of the vote. How many delegates should be allotted to each candidate?
For Bernie, , round down to 18 delegates because you can't have a decimal of a delegate.
For Hillary, .
You're given 2 gift vouchers for shopping, as shown above. The option A grants you a free second item after purchasing the product in the normal price. On the other hand, the option B gives you the discount of 40% for the first item and allows you to buy the second one at 60% cost of the first one.
Which option will save you more money?