hamburger menu
All Coursesall course arrow
adda247
reward-icon
adda247
    arrow
    arrow
    arrow
    What is the number of ordered pairs (x, y) where x, y are positive integers such that the eight digit number 74x8935y is divisible by 11?
    Question

    What is the number of ordered pairs (x, y) where x, y are positive integers such that the eight digit number 74x8935y is divisible by 11?

    A.

    6

    B.

    9

    C.

    10

    D.

    7

    Correct option is D

    Given:
    Eight digit number: 74x8935y
    The number is divisible by 11
    x and y are positive integers
    Formula Used:
    A number is divisible by 11 if the difference between the sum of digits at odd positions and the sum of digits at even positions is either 0 or a multiple of 11.
    Solution:
    Sum of digits at odd places = 7 + x + 9 + 5 = 21 + x
    Sum of digits at even places = 4 + 8 + 3 + y = 15 + y
    Difference = (21 + x) - (15 + y) = 6 + x - y
    For the number to be divisible by 11, the difference must be 0 or 11.
    Case 1: 6 + x - y = 0
    y - x = 6
    Since x and y are positive integers (from 1 to 9), the possible pairs for (x, y) are (1, 7), (2, 8), and (3, 9). This gives 3 pairs.
    Case 2: 6 + x - y = 11
    x - y = 5
    The possible pairs for (x, y) are (6, 1), (7, 2), (8, 3), and (9, 4). This gives 4 pairs.
    Total number of ordered pairs = 3 + 4 = 7
    Final Answer
    So the correct answer is (d)

    Free Tests

    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 Full Mock Test 1

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

    RRB Group D Full Mock Test 1

    languageIcon English
    • pdpQsnIcon100 Questions
    • pdpsheetsIcon100 Marks
    • timerIcon90 Mins
    languageIcon English
    TEST PRIME

    Access ‘RRB Group D’ 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
    482k+ students have already unlocked exclusive benefits with Test Prime!
    Our Plans
    Monthsup-arrow