Answer:
You didn't include any image here, but numerically, the amount of paper consumed this month is 125% compared to last month.
If last month's consumption is represented by 4 equal shapes, then the current month's consumption will be 5 shapes.
If last month's consumption is represented by 8 equal shapes, then the current month's consumption will be 10 shapes.
this pattern keeps repeating.
A proportion looks like this:

It means that the quantity a,b,c and d are in the same proportion: the ratio between a and b is the same ratio between c and d.
They are particularly useful in situation when you have an example given, and you want to extrapolate the relationship for another couple.
For example, you can think of the following problem: "Five apples cost 2 dollars. How much will 8 apples cost?"
You can build the proportion

And then solve it for x:

Answer:
144 people were originally at the party.
Step-by-step explanation:
18 boys is one fifth of the second boys population, so the second population is 18x9 = 162. The original population would be 162-18, which equals 144.