A level grade "boundaries" leak

[Wales-Bales]

It would happen if 20 percent of the cohorts got a higher mark. If the exam was easy, you would need to be in the top 20 percent to get an A.

For example, say you scored 98% and 20 percent of the class got 99% or more, then you would get a B!

^^^^ 20 percent is an arbitrary number, it's whatever the examiner decides the grading bands should be.