A trader expects a gain of 15% on his cost price. If in a week his sale is of Tk. 580, then what is his profit?

We are given selling price = Tk. 580 and expected profit of 15%
Therefore, we can easily solve this numerical, considering basic formulae of profit and loss.
Let cost price = x
Selling price = C.P. + Profit
S.P. = C.P. + (15% of C.P.) [We know that profit is gained on cost price]
580 = x + (0.15 x)
580 = 1.15 x

Therefore,
x = 504.347
Cost Price = Tk. 504.35
Now,
we have the cost price and hence,
Profit = S.P. – C.P. = 580 – 504.35
= Tk. 75.65
The trader gets a profit of Tk. 75.65