Question 262870
Let x pounds of candy A be mixed with y pounds of candy B.
Then, total x+y = 30   ...(1)
Next, candy A sells for $2.95 per pound and the other B for $3.10 per pound,
He wants to sell 30-pound mixture of two candies for $3 per pound. 
So,         2.95x+3.10y = 30*3
            2.95x+3.10y = 90  ...(2)
(1)*2.95 => 2.95x+2.95y = 30*2.95 = 88.5   ...(3)
(2)-(3) =>  3.10y-2.95y = 90-88.5
            0.15y = 1.5
            y = 1.5/0.15
            y = 10
(1)=> x+10=30
      x = 30-10 = 20