Answer:
The system of equations that represent the situation is:
r + w = 30
4r - w = 20
Explanation:
Given that Steve answered 30 questions and scored 20 points, since 1 right answer is an addition of 4 points, and 1 wrong answer is a subtraction of 1 point.
Let 1 right answer be denoted by r, and 1 wrong answer be denoted by w.
The total number of questions is 30, so
r + w = 30
The subtraction of the points from wrong answers from the points from the right answers is 20. That is;
4r - 1w = 20
