Set 9: Systems of Equations

Choice B is correct. Choice B is the correct answer. Let $x$ = pounds of $2flour and $$y = pounds of $5flour. System: $$$\begin{cases} x + y = 60 \\ 2 x + 5 y = 3.50(60) \end{cases}$$ Step 1: Simplify: $$\begin{cases} x + y = 60 \\ 2 x + 5 y = 210 \end{cases}$$ Step 2: From first: y = 60 - x Step 3: Substitute: $$$2x + 5(60 - x) = 210$$2x + 300 - 5 x = 210-3 x = -90x = 30 Solution: 30 pounds of \2flour (and 30 pounds of $5 flour) Verification: 2(30) + 5(30) = 60 + 150 = 210$$ ✓ and \frac{210}{60} = 3.50$✓ Strategic Tip: The mixture's total value = sum of individual values. Choice A is incorrect because$2(25) + 5(35) = 50 + 175 = 225 \neq 210$. Choice C is incorrect because$2(35) + 5(25) = 70 + 125 = 195 \neq 210$. Choice D is incorrect because$2(40) + 5(20) = 80 + 100 = 180 \neq 210$.