Answer: white = $13, double = $14
Explanation:
Let white chocolate chip dough = x
Let double chocolate chip dough = y
Mary: 3x + 2y = 67
Darryl: -(3x + 4y = 95)
-2y = -28
÷-2 ÷-2
y = 14
3x + 2y = 67
3x + 2(14) = 67
3x + 28 = 67
-28 -28
3x = 39
÷3 ÷3
x = 13