Ratio usually goes in questions like this :
".. 3:5. What is the bla bla bla.."
here's an example.
What is 56 hours to 9 days?
First, get how many hours in one day.
1 day = 24 hours
9*24= 216 hours
so it's 56:216.
But in ratio, you need to put it in LOWEST TERMS.
Get the GCF of them.
56:216/8:8= 7:27
So, 56 hours to 9 days is equal to the ratio 7:27.