I understand you asked for a solution without algebra, and it is very likely there's one without algebra.

The issue is it may be longer, and there is a higher chance for confusion to occur imo.

Algebra is damn important. It is okay if you find it confusing and hard to understand. Or maybe you don't like it too much.

But very soon you'll need it. It'll help a lot. So try to solve these kind of questions with algebra.

If you're not sure, ask someone for help, and have them explain to you step by step. If you can understand what's happening in the workings, algebra will be much much easier.

Best to ask your teacher tbh. Try to master simple algebra by end of this year