Answer:
21 to 28
Step-by-step explanation:
15:20
Divide each side by 5
15/5 : 20/5
3:4
we want to find the one that is 3:4
5 to 10 Divide by 5 5/5 to 10/5 1 to 2
18:25 this does not simplify
21 to 28 divide by 7 21/7 to 28/7 3 to 4
24:30 divide by 6 24/6: 30/6 4:5
