Example. Risk $10, the target gives $20. You’re right in only 4 trades out of 10: 4 × 20 = $80 won, 6 × 10 = $60 lost. Result: +$20.
It can be the other way round too. A trader guesses right 7 times out of 10, but wins $50 each time and loses $200 each time, because he doesn’t set a stop and waits for the price to come back. Seven right guesses — $350, three mistakes — $600. Result: −$250, even though he was right almost every time.