Question 255272
Let the cost of dark clay  = $ x per kg
and the cost of light clay = $ y per kg
Bryce bought 2 kg of dark clay and 3 kg of light clay, paying $22 for the clay
So we have,    2x+3y = 22  ...(1)
Then he bought 1 kg of dark clay and 2 kg of light clay,costing $13
                x+2y = 13  ...(2)
(2)*2 =>       2x+4y = 26  ...(3)
(1)-(3)=>      3y-4y = 22-26
                  -y = -4
                   y = 4
Substituting in (1), we get, 2x+3*4 = 22
                             2x = 22-12
                             2x = 10
                              x = 10/2 = 5
Therefore, the cost of dark clay  = $ 5 per kg
and the cost of light clay = $ 4 per kg