Set 13: Linear Equations

Choice D is correct. Choice D is the correct answer. 1. Define: 6% = $x$, 4% = $10000- x$. 2. Equation: $0.06x + 0.04(10000 - x) = 520$ 3. Simplify: $0.06x + 400 - 0.04 x = 520$ 4. Combine: $0.02x = 120$ 5. Divide by 0.02: $x = 6000$ Choice B is incorrect because this is the amount at 4%. Choice A is incorrect because it results from an error in the solution process. Choice C is incorrect because it results from an error in the solution process.