If an object is reflected twice over parallel line and corresponding points of the original and final translation image are 26 centimeters apart, how far apart are the parallel lines

By definition, when an object is reflected twice over parallel lines, the distance between the points of the original object and the the point of the final translation of the object, is twice the distance between the two parallel lines. Keeping this information on mind, you have:
 The distance between points of the original and final translation image is 26 centimeters. Therefore:
 2d=26 cm
 d=26 cm/2
 d=13 cm
 Therefore, the answer is: 13 cm.

If your asking how much altogether for 12 performance the answer will be 98,496.