If there were only sandwiches bought, there would be 15, if there were only salads bought there would be 20. There’s probably more than one possibility, but that’s the best I can do, considering how long it’s been since I’ve done this type of problem. I’m all the way to learning determinants, so I really have to think to remember these. Sorry in advance if this doesn’t help at all, I’m not the best at this, but I can still try.
