Afla took part in a quiz which he had to answer 30 questions. 5 marks were awarded for each correct answer and 2 marks were deducted for each wrong answer. Afla scored a total of 74 marks for the quiz. How many answeres did he mess up?
1 Answer
See a solution process below:
Explanation:
First, let's call:
 The number of correct answers:
#a#  The number of wrong answers:
#w#
Next, from the information in the problem we can write two equations:

Equation 1:
#a + w = 30# 
Equation 2:
#5a  2w = 74#
Step 1) Solve the first equation for
Step 2) Substitute
Because you cannot get a question part wrong