Let's define the variables and use the given information to find the required expression.

Given:

• Total number of questions: 30
• Marks awarded for each correct answer: 3
• Marks deducted for each incorrect answer: 1
• Number of unattempted questions: 4
• Total marks scored by Reiner: 62

Let:

• $x$ = number of correct answers

Since Reiner left 4 questions unattempted, the number of attempted questions is:

$30 - 4 = 26$

Therefore, the number of incorrect answers can be expressed in terms of $x$:

$\text{Number of incorrect answers} = 26 - x$

This is because the total number of attempted questions is 26, which is the sum of correct and incorrect answers.

Would you like more details or have any questions?

Here are some related questions that might interest you:

1. How many correct answers did Reiner have?
2. What would Reiner's score be if he attempted all questions?
3. How would the total score change if each wrong answer deducted 2 marks instead?
4. If Reiner attempted 2 more questions and got them both correct, what would his new score be?
5. What is the minimum number of correct answers Reiner needs to get a positive score?

Tip: Always carefully analyze the problem and define variables clearly to set up the correct expressions.