For the mix you need 60 Ib of nuts and raisins, and 60 lb of mix will sell for $300. Let <em>x</em> be the weight of nuts and <em>y</em> the weight of raisins needed for the mix. Total weight = <em>x</em>+<em>y</em> = 60, so <em>y</em> = 60 - <em>x</em> Total value = 6<em>x</em> + 3<em>y</em> = 300. From the above, we can substitute the <em>y</em> for 60 - x: Total value = 6<em>x</em> + 3(60 - <em>x</em>) = 300, which we can simplify to: 6<em>x</em> + 180 - 3<em>x</em> = 300, and simplify again to: 3<em>x</em> = 120, and again to: <em>x</em> = 40. We can now calculate<em> y</em> from the first equation y = 60 - <em>x</em>, so: y = 20. 40 lb of nuts and 20 lb of raisins. Check: 40 lb x $6/lb = $240, and 20 lb x $3/lb = $60, $240 + $60 = $300.