Set 16: Linear Equations

Choice A is correct. Choice Ahoice D is the correct answer. 1. Define: Mary = $x$, John = $3x$. 2. In 5 years: Mary = $x+5$, John = $3x+5$. 3. Equation: $3x + 5 = 2(x + 5)$ 4. Solve: $3x + 5 = 2 x + 10 \rightarrow x = 5$ 5. Verify: Mary 5, John 15. In 5 years: Mary 10, John 20. $20= 2(10)$ ✓ Choice Ahoice C is incorrect because this is John's age. Choice Ahoice B is incorrect because it results from an error in the solution process. Choice Ahoice D is incorrect because it results from an error in the solution process.