Question

    S1 is a series of 5 consecutive prime numbers starting

    from the second lowest prime number. S2 is a series of 5 consecutive odd numbers whose first term is equal to the fourth term of S1. S3 is a series of 5 consecutive even numbers with average 6. What is the difference between the greatest term of S3 to the middle term of S2?
    A 2 Correct Answer Incorrect Answer
    B -2 Correct Answer Incorrect Answer
    C -5 Correct Answer Incorrect Answer
    D 5 Correct Answer Incorrect Answer
    E -3 Correct Answer Incorrect Answer

    Solution

    Second lowest prime number = 3.
    S1: 3, 5, 7, 11 and 13
    First term of S2 = 4th term of S1 = 11
    S2: 11, 13, 15, 17 and 19.
    Let S3: a, a + 2, a + 4, a + 6 and a + 8
    Average of S3 = 6
    (5a + 20)/5 = 6
    => a + 4 = 6
    => a = 2.
    S3: 2, 4, 6, 8 and 10
    Difference between the greatest term of S3 to the middle term of S2
    = 10 - 15 = −5

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