The score on a trivia game is obtained by subtracting number of incorrect answers from twice the number of correct answers. If a player answered 40 questions and obtained a score of 50, how mary questions did the player answer correctly?

30

Step-by-step explanation:

I solved this question algebraically. First a variable (I used 'c') is introduced into the equation (for the number of correct answers). Thus we get the equation;

2c - (40 - c) = 50

solving this ...

2c - 40 + c = 50

3c = 90

c = 30

So the number of correct answers is 30. (30*2-10=50)

[Alternatively we can use a variable for the number of incorrect answers and get; 2 * (40 - a) - a = 50, and solve this equation but this method is longer as you'll need to subtract this answer from 40 to get the number of correct responses.]