Answer:
360 boxes
Step-by-step explanation:
The number of boxes in the warehouse before 60 boxes were added is;
n = 12k .... equation 1
where k is the constant of the number of stacks and n is the number of boxes.
The number of boxes after the 60 boxes were added is;
n + 60 = 14k ... equation 2
substitute the value of n in equation 2 for equation 1:
12k + 60 = 14k
60 = 14k - 12k
60 = 2k
k = 60 / 2 = 30
The number of boxes in the warehouse before 60 boxes was added is;
n = 12 * 30 = 360