Rekha loves creating new shades of paint. One day, he decided to mix red paint and white paint to make a light pink colour. He found that the perfect shade is formed when the paints are mixed in the ratio \(2:3\).
Based on this situation, answer the following:
1. If Rekha uses 8 litres of red paint, how many litres of white paint should he add to keep the same ratio?
2. If he prepares 15 litres of the mixture, find the quantity of red paint (in litres).
3. If he prepares 15 litres of the mixture, find the quantity of white paint (in litres).
4. If he accidentally adds 12 litres of white paint, how much red paint (in litres) must he mix to maintain the ratio?