Video Transcript
The total number of students in the
first, second, and third grades at a primary school is 285 in the ratio seven : four
: eight. Calculate the number of students in
each grade.
We can share a total, in this case,
285 students, in a given ratio by following three steps. Firstly, we find the sum of the
ratios. Seven plus four plus eight is equal
to 19. Our second step is to divide the
total by this answer. 285 divided by 19 is equal to
15. This is equal to one part or one
share of the ratio.
Our final step is to multiply the
value for one part by each of the ratios. 15 multiplied by seven is 105. 15 multiplied by four is equal to
60. 15 multiplied by eight is equal to
120. As the seven corresponded to the
number of first graders, there are 105 students in first grade, 60 students in
second grade, and 120 students in third grade. It is always worth checking our
answers by adding the values to ensure this makes the total. 105 plus 60 plus 120 is equal to
285. This method works for sharing any
total between any number of ratios.
