If 6 stones weigh 30 grams, how many stones weigh 55 grams?

11 stones.

Step-by-step explanation:

If 6 stones weigh 30 grams, then 1 stone would be 5 grams.

Fractions are fun so let's do this:

1 stone = x stones

5 grams 55 grams

To get 5 to 55, you multiply 11. So do that on the numerator, and bam, you got 11 stones.