Blue book math problem. Need help.

<p>Pg.843 no.16 (the explaination on cc and cb aren’t too clear to me)</p>

<li>In a mixture of peanuts to cashews, the ratio by weight of peanuts to cashews is 5 to 2. How many pounds of cashews will there be in 4 pounds of this mixture?</li>
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<p>First, when dealing with ratios, which represent a part to a part, the total of the ratio is usually important. In this case, the total is 7 (5+2). Use the total to figure out the FRACTION of the mix that are cashews. In this case, 2/7. Then just set up a proportion that compares (cashew ratio)/(total mix as a ratio) = (pounds of cashews)/(pounds of mix). Therefore, 2/7 = x/4. Solve for x = 8/7</p>