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.