you need 50 pounds of two commodities costing $1.25 and $1.26 per pound,verify that the total cost is y=1.25x+1.60(50-x),where x is the number of pounds of the less expensive commodity.

Answer 1

cost = rate * quantity

Since the two quantities add to 50, if one is x, the other is 50-x.

However, I fail to see the connection between 1.26 and 1.60...