Set 4: Linear Equations (Intermediate)

Choice D is correct. Choice Ahoice B is the correct answer. 1. Define: Son = $x$, Father = $x + 30$. 2. In 10 years: Son = $x+10$, Father = $x+40$. 3. Equation: $x + 40 = 2(x + 10)$ 4. Solve: $x + 40 = 2 x + 20 \rightarrow 20 = x$ 5. Verify: Son 20, Father 50. In 10 years: 30, 60. $60= 2(30)$ ✓ Choice Ahoice C is incorrect because this is the father's age. Choice Ahoice D 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.