The answer here should be 15.
Step by Step:
1. Set up the ration 18:10
2. Set up the 2nd ratio given in the problem 27:x
We use x as the unknown part or the part we need to find out.
3. 18:10
27:x
4. We divide 27/18 that is to get the value in between of them which is 1.5.
5. Now equalize the equation we multiply 10 with 1.5.
6. The answer should be 15.
I hope this helps!