Dinesh bought two radios for Rs. 1920. He sold one at a profit of 20% and or at a loss of $$6\frac{2}{3}$$% . If selling price of both radios are same, n find cost price of both radios = ?

Let first radio CP is x second radio CP is 1920 - x
As is given,
$$x \times \frac{{\left( {100 + 20} \right)}}{{100}} = \left( {1920 - x} \right) \times $$      $$\frac{{\left( {100 - \frac{{20}}{3}} \right)}}{{100}}$$
$$\eqalign{ & 120 \times x = \left( {1920 - x} \right) \times \left( {\frac{{280}}{3}} \right) \cr & 360 \times x = \left( {1920 - x} \right) \times 280 \cr & 640 \times x = 1920 \times 28 \cr & \therefore x = 840 \cr} $$
Hence, second radio cp is 1920 - x
= 1920 - 840
= 1080
CP of both Radio = 840 and 1080