Robert took a test of 20 questions. The test was graded by giving 10 points for each correct answer and deducting 5 points for each incorrect answer. Robert answered all 20 questions and received a score of 125. How many wrong answers did he have?
Answer
He had 5 wrong answers. If he had answered all 20 questions correctly, he would have scored 200. Since he scored 125, this means he lost 75 points. We must deduct 15 points for each wrong answer; 10 points that he did not earn for getting it right, plus the 5 points that are deducted for the answer being wrong. 75 lost points divided by 15 equals 5 wrong answers.
