Can u please answer all three and in 20-30 minutes please or quicker if u can please I just not understanding the math they are giving me

18). 16:80 is the ratio but in simplest form is; 5:0
19). 36:54 is the ratio but in simplest form is; 2:3
20). 12:24 is the ratio but in simplest form is; 1:2
hope that helps:D