The manager of a farmer's market has 350 lb of grain that costs $1.50 per pound. How many pounds of meal costing $0.80 per pound should be mixed with the 350 lb of grain to produce a mixture that costs $1.29 per pound?
lb
If he uses x lbs of meal, then the value of the parts must equal the value of the final mix:
1.50*350+ 0.80x = 1.29(350+x)