How many pounds of peanuts that cost $0.70 per pound and cashews that cost $0.90 per pound can be combined to make 300 pounds of a mixture that will sell $0.75 per pound?

Question

1942 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-09-18T00:37:12

I found:
$225 p o u n d s$ $225 pounds$ of peanuts;
$75 p o u n d s$ $75pounds$ of cashews.

Call the quantity of peanuts $p$ $p$ and cashews $c$ $c$ so you get:
${(p+c=300),(0.7p+0.9c=0.75*300):}$

From the first you get:

$p=300-c$

substitute into the second:

$0.7(300-c)+0.9c=225$
$210-0.7c+0.9c=225$
$c=75pounds$
back into $p=300-c$ you get:
$p=300-75=225pounds$