49. Each contestant at a math competition starts with 30 points. A contestant earns 10 points for each question answered correctly and loses 5 points for each question answered incorrectly. Sammi answered twice as many questions correctly as incorrectly, finishing with 150 points. How many questions did Sammi answer correctly?

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

First of all, set the wrong ones as i and the right ones as c, so c=2i; then because the total score is 150, the expression 30+10c-5i=150 is obtained, and then the two formulas are combined You can solve it immediately