hamburger menu
All Coursesall course arrow
adda247
reward-icon
adda247
    arrow
    arrow
    arrow
    Select the number from among the given options that can replace the question mark (?) in the following series.8, 17, 35, 71, ?
    Question

    Select the number from among the given options that can replace the question mark (?) in the following series.
    8, 17, 35, 71, ?

    A.

    141

    B.

    133

    C.

    143

    D.

    142

    Correct option is C

    Given8, 17, 35, 71, ?
    Logic: (Previous Number ×\times 2) + 1 = Next Number given series.
    ×\times​ 2 = 16, 16 + 1 = 17
    17 ×\times 2 = 34, 34 + 1 = 35
    35 ×\times​ 2 = 70, 70 + 1 = 71
    Similarly,
    71 ×\times​ 2 = 142, 142 + 1 = 143
    Thus, correct option is (c).

    Free Tests

    Free
    Must Attempt

    CBT-1 Full Mock Test 1

    languageIcon English
    • pdpQsnIcon100 Questions
    • pdpsheetsIcon100 Marks
    • timerIcon90 Mins
    languageIcon English
    Free
    Must Attempt

    RRB NTPC UG Level PYP (Held on 7 Aug 2025 S1)

    languageIcon English
    • pdpQsnIcon100 Questions
    • pdpsheetsIcon100 Marks
    • timerIcon90 Mins
    languageIcon English
    Free
    Must Attempt

    CBT-1 General Awareness Section Test 1

    languageIcon English
    • pdpQsnIcon40 Questions
    • pdpsheetsIcon30 Marks
    • timerIcon25 Mins
    languageIcon English
    TEST PRIME

    Access ‘RRB NTPC’ Mock Tests with

    • 60000+ Mocks and Previous Year Papers
    • Unlimited Re-Attempts
    • Personalised Report Card
    • 500% Refund on Final Selection
    • Largest Community
    1 month
    students-icon
    383k+ students have already unlocked exclusive benefits with Test Prime!
    Our Plans
    Monthsup-arrow