Dinesh bought two radios for Rs. 1920. He sold one at a profit of 20% and other at a loss of 62/3 % . If the selling price of both radios are same, then find the cost price of both radios = ?

Answer: Option B

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