A store sells cashews for 500 per pound and peanuts for 200

A store sells cashews for $5.00 per pound and peanuts for $2.00 per pound. The manager decides to mix 70 pounds of peanuts with some cashews and sell the mixture for $3.00 per pound. How many pounds of cashews should be mixed with the peanuts so that the mixture will produce the same revenue as would selling the nuts separately? There should be pounds of cashews in the mixture. (Type an integer or a decimal.)

Solution

70 pounds of peanut and \'x\' pounds of cashew to be sold for 3$ per pound;
Revenue when sold combined = 3(70+x)
Revenue when sold individually = 5*x + 2*70
These both revenues are to be equal;
Thus: 3(70+x) = 5x+140
210 + 3x = 5x +140
2x=70 or x=70/2 = 35 pounds;

Thus, 70 pounds of peanuts must be mixed with 35 pounds of cashew to generate the same revenue;