Video Transcript
The pie chart shows the results of
a survey of what fruits students prefer. Given that 30 students completed
the survey, how many students prefer peaches?
We can see from the pie chart that
the percentage of students that prefer peaches was 40 percent. As there were 30 students surveyed
in total, we need to calculate 40 percent of 30. There are lots of ways of
calculating this. One way would be to convert the
percentage into a decimal first. As the word percent means out of
100, we can convert from a percentage to a decimal by dividing by 100. Therefore, 40 percent is equivalent
to 0.4. The word “of” in mathematics means
multiply. We need to multiply 0.4 by 30. 0.4 multiplied by 10 is equal to
four. Therefore, 0.4 multiplied by 30 is
equal to 12. 12 of the 30 students in the survey
prefer peaches.
An alternative method to calculate
40 percent of 30 would be to turn the percentage into a fraction. 40 percent is the same as 40 over
100, so we would need to multiply this by 30. We could simplify the fraction by
dividing the numerator and denominator by 10. 30 and 10 are also divisible by 10,
leaving us with four multiplied by three. Once again, we get an answer of 12
students.
A third method would be to
calculate 10 percent of 30 first. We know that to find 10 percent, we
divide the quantity by 10. And 30 divided by 10 is three. We can then multiply this answer by
four to calculate 40 percent of 30. All three of these methods give us
an answer of 12 students.