Hello khanmaria-ga,
There are 12 boys in the class and 16 girls.
There are several ways to solve this problem.
One way is to split the 28 students into 7 groups of 4. I know this
because 4 x 7 = 28 (or 28 divided by 7 is 4).
Each asterisk (*) represents 1 student.
Group 1 * * * *
Group 2 * * * *
Group 3 * * * *
Group 4 * * * *
Group 5 * * * *
Group 6 * * * *
Group 7 * * * *
If you count the asterisks, you will see that there are a total of 28
of them.
The fraction 4/7 represents 4 of the 7 groups.
If you count the total number of asterisks in 4 groups, you come up
with 16.
Group 1 * * * *
Group 2 * * * *
Group 3 * * * *
Group 4 * * * *
Therefore, there are 16 girls in the class.
Since 28 - 16 = 12, there are 12 boys in the class.
16 girls + 12 boys = 28 total students.
You can also solve this problem by multiplying the fraction 4/7 by 28.
4 x 28 112
4/7 x 28 = -------- = ------ = 16 girls. (112 divided by 7 is 16)
7 7
==> 28 - 16 = 12 boys.
You can also solve the above equation as follows:
4 x 28 28
4/7 x 28 = -------- = 4 x ---- = 4 x 4 = 16 girls.
7 7
==> 28 - 16 = 12 boys.
Another way to solve the problem is that, if 4/7 of the class is
girls, then 3/7 must be boys (4/7 + 3/7 = 7/7 = 1).
Then you know that 3 groups of students will have 12 students in it.
Group 1 * * * *
Group 2 * * * *
Group 3 * * * *
Therefore there are 12 boys in the class.
OR
3 x 28 84
3/7 x 28 = -------- = ------ = 12 boys. (84 divided by 7 is 12)
7 7
OR
3 x 28 28
3/7 x 28 = -------- = 3 x ---- = 3 x 4 = 12 boys.
7 7
I hope you have found this information helpful. If you have any
questions, please request clarification prior to rating the answer.
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None. I have a degree in engineering and I teach basic math and
algebra part time. |
