Should I send only ACT or both SAT and ACT

But. It’s not Composite or SAT total. It’s the sections. You have to realize it’s not about score perfection. That misleads many kids. Your app will tell a whole story. Or not.

So it’s 770/770 or 800/740 or? The lower score is presumably not math?

Make sure you have a good read on what MIT does want, besides these test scores. Rigor, grades (not just gpa,) AP scores, ECs, and your activation, etc. Hope you’ve read their blogs.