2022 · Q119
A test consists of 25 MCQs. Each correct answer gives +4 marks and incorrect answer gives -1 mark. If a candidate scores 74 marks, then how many questions were left unattempted?
general-mental-abilityquantitative-aptitude
- A4
- B3
- C5
- D9
Explanation
Let c = correct, w = wrong, u = unattempted: c + w + u = 25 and 4c − w = 74. Then w = 4c − 74 ≥ 0 forces c ≥ 19; c = 19 gives w = 2 and u = 25 − 21 = 4, which checks out (4 × 19 − 2 = 74). Any larger c would make u negative, so exactly 4 questions were left unattempted.