1. **Problem statement:** Paul is currently 1.86 m tall and shrinks 1 mm (0.001 m) per year. Marrit is 1.75 m tall and grows 1 cm (0.01 m) per year. We want to find after how many years they will be the same height. 2. **Set up the equation:** Let $x$ be the number of years after which they are the same height. Paul's height after $x$ years: $$1.86 - 0.001x$$ Marrit's height after $x$ years: $$1.75 + 0.01x$$ 3. **Equate their heights:** $$1.86 - 0.001x = 1.75 + 0.01x$$ 4. **Solve for $x$: ** $$1.86 - 1.75 = 0.01x + 0.001x$$ $$0.11 = 0.011x$$ $$x = \frac{0.11}{0.011}$$ $$x = 10$$ 5. **Interpretation:** After 10 years, Paul and Marrit will be the same height. **Answer:** (C) over 10 years --- Since the user asked to solve and correct answers, only the first question is solved as per instructions.