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.
135 = 3 times 45
135 = 5 times 27
135 = 9 times 15
135 = 3 times 3 times 3 times 5 or 
times 5
