Answer:
3/8 = x/160
Step-by-step explanation:
First, you need to find the total amount of boys and girls, so you add 3+5.
3+5= 8
So 8 is the total, and out of 8 people, 3 of them are boys. Now that you have that, you can set up the first part of the proportion.
3/8
Now, what information does it give you about the people in the grade? It tells you the total amount, but not the number of boys.
3/8 = out of 8 people, 3 of them are boys.
x/160 = out of 160 people in a grade, x of them are boys.
So your final proportion would be 3/8 = x/160.
Bonus:
If you need to find the number of boys in a grade, just solve the proportion as normal, which would give you 60. So there are 60 boys out of 160 people in a grade.
