1. The problem states that every kilogram of paper earns 5 points. The table shows the points earned for 1 to 6 kilograms. 2. When the number of kilograms is doubled, the points also double because points are directly proportional to kilograms. For example, if $n=2$, points $P=10$, which is double the points for $n=1$. 3. When the number of kilograms is tripled, the points triple for the same reason. For example, if $n=3$, points $P=15$, which is triple the points for $n=1$. 4. To find how many kilograms are needed to earn 500 points, we write the equation: $$P = 5n$$ Given $P=500$, solve for $n$: $$500 = 5n$$ Divide both sides by 5: $$n = \frac{500}{5} = 100$$ So, the Grade 8 class needs to collect 100 kilograms of paper to earn 500 points. 5. Collecting waste papers helps clean the environment by reducing litter, saving trees, and decreasing pollution caused by paper waste. 6. Items that can be made from recycled paper include notebooks, cardboard boxes, paper bags, and other paper products. Final answers: - Doubling kilograms doubles points. - Tripling kilograms triples points. - 100 kilograms needed for 500 points. - Recycling helps reduce waste and protect the environment. - Recycled paper can be made into various useful items.