📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!

    Question

    How many 5-digit numbers can be formed using digits

    1–7 such that digits are odd-even-odd-even-odd?
    A 125 Correct Answer Incorrect Answer
    B 144 Correct Answer Incorrect Answer
    C 165 Correct Answer Incorrect Answer
    D 100 Correct Answer Incorrect Answer

    Solution

    ATQ,

    Odd digits = 1,3,5,7 = 4; Even = 2,4,6 = 3. Pattern: O-E-O-E-O → 3 odd used, 2 even used. Odd: 4P3 = 24, Even: 3P2 = 6 → Total = 24×6=144 → 144 numbers.

    Practice Next
    More Permutation and combination Questions
    ask-question