Normally to compare 2 fractions, I would say to find a common denominator so you can compare them directly, however on this problem we can just use a little common sense to figure it out...
Look at 6/11. 6 is approximately half of 11 so 6/11 is approximately 1/2. Now look at 9/10. If 10/10 is one whole, 9/10 is approximately 1.
So you can look and see that 6/11 < 9/10 because 1/2 < 1