A shopkeeper expects a gain of 22.5% on his cost price. If in a week, his sale was of 784 Tk, what was his profit?

Question: A shopkeeper expects a gain of 22.5% on his cost price. If in a week, his sale was of 784 Tk, what was his profit?

Solution:
Given,
Selling price = 784 Tk.

For a gain of 22.5%,
The cost price can be = 122.5

Cost price = (100/122.5) × 784 Tk.
= (1000/1225) × 784 Tk.
= 640 Tk

Therefore, Profit = 784 - 640 Tk.
= 144 Tk.