In a quiz game, a player earns 5 points for every correct answer and loses 3 point for every wrong answer. If Steve’s score is 0 after answering 40 questions, how many questions did he answer correctly?
My approach isn't very mathematical, I'm sure there is a better approach but here's mine. Some mathematical principle but most trial and error.
You want to find a common multiple. If Steve's score is , then this meant that he lost on more occasion that won.
The common multiple of and are:
etc.
At which value would the alternative pair add upto . This would be because:
The alternative pair and add to make .
This means, Steve lost times and won times.