I can't think of any way to solve that problem, can anyone help?

The fact that the OP stated he’s 15, and judging by the way the question is written and the information given, it’s safe to say they are looking for the simplistic answer. To take the question and purposely complicate it makes zero sense in this case.

Precisely. If a student is more mathematically mature and advanced, it is unlikely they'd be working these kind of problems anyway. I have always been very good at making simple things more complex than necessary, but not in this case. That commenter is deliberately complicating things, which is more likely to confuse the OP and frustrate them than anything. That is the behaviour that drives students away from mathematics.

/r/learnmath Thread Parent