(5/4)•(4/3)•(3/5)
So you multiply all of them basically
Since the ratio is 3:4, and 12/4 is 3 than you do 3x3 and get 9 so the answer is 9:12 or 9 boys and 12 girls. To check your answer, you can do 3/4 (for 3:4) and that is 0.75. If you do that with 9:12 you also get 0.75.
I don't recognize this problem, please make sure the input is complete.
17 subtracted from x is:
x-17
x-17 is AT LEAST 19, meaning your inequality sign is going to be a greater than or equal to sign, since it says AT LEAST.
Your expression will be:
x-17≥19