Let us assume the original price of the coats before mark up = x
Cost of the coats after mark up = $3000
Percentage of mar up on the coats = 50%
Then
150x/100 = 3000
150x = 300000
x = 300000/150
= 2000 dollars
From the above deduction, it can be concluded that the actual cost of the coats were $2000. I hope the procedure is clear enough for you to understand.