Hello!
For every 1 blue marble there are 5 greens
You add the numbers in the ratio
1 + 5 = 6
Divide this number from the amount of marbles
60 / 6 = 10
Multiply the ratio by this
1 * 10 = 10
5 * 10 = 50
There are 10 blue marbles and 50 green ones
The answer is 10
Hope this helps!