Question

Please help me people

Answer 1

Working:
120/24 = 5

so 100/5 will give you the answer which is 20. 
She should sell 20 band posters.
Because the scale is 5.

Answer 2

Answer: 20 posters

How I got it:
Ratio of movie to band posters is 120:100 = 6/5.
After selling 24 movie posters she has 96. So now it is 96/x = 6/5
6x = 480. Divide 480 by 6 and get x = 80.
So she has to sell 100:80 or ---> 20 band posters <---.

Hope this helped!