The manager of a farmer's market has 500lb of grain that costs $1.20 per pound. How many pounds of meal costing $.80 per pound should be mixed with the 500lb of grain to produce a mixture that costs $1.05 per pound?

Answer 1

let the amount to be added be x lb

1.2(500) + .8x = 1.05(500+x)
600 + .8x = 525 + 1.05x
-025x = -75
x = -75/-.25 = 300

300 lb of the cheaper grain should be added