Question

In a multiple choice test there are 6 questions. Four alternative answers are given for each question, of which only one answer is correct. If a candidate answers all the questions by choosing one answer for each question, then the number of ways to get exactly 4 correct answers, is-

• A. 4⁶–4²
• B. 135
• C. 9
• D. 120

Answer 1

Answer: (B)

135

Answer 2

Sol. Explanation:

Four correct answers can be chosen in ⁶C₄ ways and 2 wrong answers can be given in 3 × 3 = 9 ways. ̃ answer

= ⁶C₄ × 9 = 135