Answer:
10.46
Explanation:
Let the Number of additional pair = x
Ware house A :
855 + 92x - - - (1)
Warehouse B:
Initial cost per pair before 9
= 810 / 9 = $90
Additional 7% for pairs after 9
1.07 * 90 = 96.3
810 + 96.3x - - - (2)
810 + 96.3x = 855+ 92x
96.3x - 92x = 855 - 810
4.3x = 45
x = 45 / 4.3
x = 10.46
Additional pair be 10.46