Selling price of washing machine = ₹ 13,500
Loss percent = 20%
Let the cost price of washing machine be₹ x.
Since, Loss = Loss% of C.P.
⇒ Loss = 20% of ₹ x = 20/100 x ₹x =1/5 ₹x
Therefore,S.P. = C.P. – Loss
Hence, the cost price of washing machine is ₹ 16,875.