Answer:
She used 22 paper fans, 66 balloons, and 32 streamers.
Explanation:
In order to solve this problem, we need to find out the value of the paper fans. Because we need to find out the balloon amount, which is 3 times as much. The amount of streamers is 12 fewer than two times. We can't find it out just yet since we don't know the value of the paper fans. To find it out:
First, let's call the amount of paper fan as "x".
Then, we need to find out the amount of balloons. It is 3 times x. Which is the same as 3x.
The equation is now x + 3x + (?) = 120
We need to find out the amount of the (?).
So, to do that, it says the value is 12 fewer than 2 times the value of x. (x, because it is the amount of paper fans.)
It should be 2x-12.
Now, the equation is x+3x+2x-12=120.
Once we solve it, we know "x" is 22.
Now, we can multiply 3 by 22. Which is 66.
Then we can multiply 22 by 2, which is 44, and subtract 12, which is 32.
To double check, 22 + 44 + 32 = 120.
That's your answer!