1. **Stating the problem:** You get 20 cents for each correct answer and pay 10 cents for each wrong answer. After 30 questions, your profit is 1.80 dollars. 2. **Define variables:** Let $x$ be the number of questions you got right. Then the number of questions you got wrong is $30 - x$. 3. **Form the equation:** Profit = (money earned from right answers) - (money paid for wrong answers). $$\text{Profit} = 0.20x - 0.10(30 - x)$$ 4. **Set profit to 1.80:** $$0.20x - 0.10(30 - x) = 1.80$$ 5. **Simplify the equation:** $$0.20x - 3 + 0.10x = 1.80$$ $$0.30x - 3 = 1.80$$ 6. **Solve for $x$:** $$0.30x = 1.80 + 3$$ $$0.30x = 4.80$$ $$x = \frac{4.80}{0.30} = 16$$ 7. **Interpretation:** You got 16 questions right. **Final answer:** $x = 16$ questions right.