No, there is not common ratio...
0.972 (common ratio is 0.3...10.8*.3*.3)
you can use the geometric mean to find this center value easily...
(18*8)^(1/2)=12

This is equal to:

When you add a negative number, it turns into subtraction.
First, I would change it to mixed numbers:

Now, you need to change the denominators to make sure they are the same on both fractions. I changed the first fraction's denominator to 4 so they match. You can do this by multiplying the numerator by 2:

Now, you simply subtract:
10-9=1
1/4 is your answer.
I hope this helps :)
Answer:
b
Step-by-step explanation:
Oldest = 2x
Middle = x + 5
Youngest = x
2x + x + 5 + x = 57
combine like terms
4x + 5 = 57
subtract 5 from both sides
4x = 52
divide both sides by 4 to isolate x
x = 13
Oldest = 2x = 2(13) = 26
Middle = x + 5 = 13 + 5 = 18
Youngest = x = 13