Answer:
3B
Step-by-step explanation:
The greatest common factor is the greatest number that will divide two values. We have two values 3B and 30B. Each has numbers which multiply together to give the number. We need to find the highest value or most in common they share. Each has the factors:
3B: 1,3,B
30B: 1, 3, 5, 6, 10, B
Both have 3 and B has factors. Our GCF is these two factors.
(y^2)^5 × y^8
Use the rule:

To get:
y^10, then, use the rule:

To eventually get:
y^(10+8) = y^18 or: y18 seeing as you wrote it like that.
To solve this problem you must apply the proccedure shown below:
1. You have the following ratio given in the problem above:
11:1
2. You can rewrite that ratio as below:
11/1=11
3. Then, to find three equivalent ratios, you only need to multiply the numerator (11) and the denominator (11) by the sam number. Therefore, you have:
11x2/1x2=22/2=11
11x3/1x3=33/3=11
11x4/1x4=44/4=11
Therefore, as you can see, the answer is:
22:2
33:3
44:4