Set 16: Linear Equations (Advanced)

Choice C is correct. Choice C is the correct answer. 1. Equations: $x + y = 20$, $2x + y = 30$ 2. Subtract 1 st from 2 nd: $(2 x + y) - (x + y) = 30 - 20 \rightarrow x = 10$ 3. Find y: $10+ y = 20 \rightarrow y = 10$ Choice D is incorrect because $2(5)+15=25 \neq 30$. Choice B is incorrect because $2(8)+12=28 \neq 30$. Choice C is incorrect because $2(6)+14=26 \neq 30$.