I'm devising a system to work out if a student will get a particular grade based on their first year result.
If they get 90% of marks in their second year and 80% of marks overall, they get an A* (a British A+).
As an example, let's say they've gotten 80/100 marks in year one and are about to embark on year two, in which 120 marks are available.
How can I calculate how many marks (out of 120) they'd need to get in year two to get an A*, preferably expressed as a single equation?
P.S. Sorry if I've made a mistake with the tag. I'm new here and there wasn't a 'percent' tag, but a few other percent qs use the stats tag. Thanks.