One Trader calculates the percentage of profit on the buying price and another calculates on the selling price. When their selling prices are the same, then the difference of their actual profit is Rs 85 and both claim to have made 20% profit. What is the selling price for each?

Let Selling Price (same for both) = $x$

For First Trader (calculating on CP):

If CP = $p$

$20\% \text{ profit means: } x = p + \frac{20p}{100} = 1.2p$

$\therefore p = \frac{x}{1.2}$

Actual profit = $x - \frac{x}{1.2} = \frac{0.2x}{1.2} = \frac{x}{6}$

For Second Trader (calculating on SP):

$20\% \text{ profit on SP means: Profit} = \frac{20x}{100} = 0.2x$

If CP = $q$

$x - q = 0.2x$

$q = 0.8x$

Actual profit = $x - 0.8x = 0.2x$

Given that difference in profits = $85$

$0.2x - \frac{x}{6} = 85$

$\frac{6(0.2x) - x}{6} = 85$

$\frac{1.2x - x}{6} = 85$

$\frac{0.2x}{6} = 85$

$0.2x = 510$

$x = 2550$

Therefore, the selling price is Rs $2550$