Multiple choice general knowledge math & puzzles

In objective test a correct answer score 4 marks and on a wrong answer 2 marks are negative . a student score 480 marks from 150 question. how many answer were correct?

  1. 120

  2. 130

  3. 90

  4. 110
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let c be correct answers, w be wrong. Total: c + w = 150, so w = 150 - c. Score: 4c - 2w = 480. Substituting: 4c - 2(150 - c) = 480, 4c - 300 + 2c = 480, 6c = 780, c = 130. Therefore 130 answers were correct and 20 were wrong. Verification: 130 × 4 - 20 × 2 = 520 - 40 = 480.

AI explanation

To solve this question, we can set up a system of equations. Let's assume that the number of correct answers is x.

According to the given conditions:

  • A correct answer scores 4 marks
  • A wrong answer scores -2 marks

We can set up the equation to find the total score: 4x - 2(150 - x) = 480

Simplifying the equation: 4x - 300 + 2x = 480 6x - 300 = 480 6x = 780 x = 130

Therefore, the number of correct answers is 130.

So, the correct answer is option B) 130.

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