Waste and earth problems – trash sorting task

Real life applications of Math – the main purpose of the tasks. Homework, classwork or exams must be fun and also improving mathematics education. Cool math game combinated with Earth problems and social responses thinking is another goal of the tasks.

Why do we need to sort waste? Trash and especially plastic demage can be a topic of conversation, even during math lessons. 

It is a textual exercise that uses inverse proportionality. Could you solve it?