percentage including money and profit

Question

I bought a bike for 30 Euro, the next day I sold the bike for 250 Euro, What percentage profit did I make in percentage? my friend say that he got for his answer 733,3 percent but I said that I got 73 percent, who is right?

Answer 1

You can estimate it.

• $100$ % would be $30$ EUR. But the profit is about $10$ times larger
• $73$ % is less then $100$ %, that would be valid for a profit less than $30$ EUR

The profit is $250$ EUR - $30$ EUR = $220$ EUR.

The percentage is $220$ EUR / $30$ EUR = $7.\bar{3}$ EUR = $733.\bar{3} / 100$ EUR. Or in other words $733.3$ % (rounded to one digit after the period)

Answer 2

Consider $(250$ EUR $-30$ EUR$)/$ $30$ EUR = $7.\bar{3}$.

Therefore you made about 733.3 % profit and your friend was right.