What would you say:
10 % is or 10% are, I have found both on the internet but which is correct?
I think the question was about whether to use the singular is or the plural are.
This rule should work most of the time:
If you are talking about count nouns, use are. If you are talking about non-count nouns or a percentage of a singular item, use is.
Only 20% of the students are finished with their test.
Only about 10% of the cake is left.
About 50% of the air is left in this balloon.
[not a teacher]
Of course - good example of the eye glossing the text on a screen.