So I think it is option 4. 20/ 27 as when you first make the ratio equal you get the answers - a:b is 8:12 and b:c is 12:15 and then you get the equation 8+12/12+15 ( we replaced 8,12 and 15 with the terms a,b and c ) So when you solve this equation you get the answer 20/27. Please let me know if this is correct.
So I think it is option 4. 20/ 27 as when you first make the ratio equal you get the answers - a:b is 8:12 and b:c is 12:15 and then you get the equation 8+12/12+15 ( we replaced 8,12 and 15 with the terms a,b and c ) So when you solve this equation you get the answer 20/27. Please let me know if this is correct.