If selling price is doubled, the profit sextuples. Find the profit percent?

Question: If selling price is doubled, the profit sextuples. Find the profit percent?

Solution:
Let,
The cost price be Tk.100 and sell price be Tk. x,
Then,
The profit is (x - 100)

Now, The sell price is doubled, then the new sell price is 2x
New profit is (2x - 100)

ATQ,
6(x - 100) = 2x - 100
⇒ 6x - 600 = 2x - 100
⇒ 6x - 2x = 600 - 100
⇒ 4x = 500
∴ x = 125

Then the Profit = (125 - 100) = 25
Hence the profit percentage is = (25/100) × 100 %
= 25%