New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    A number series is given as below. Study the following information carefully and answer the given questions.

    Series I:  16 21 36 81 209 621 1836 Series

    II:  20 60 240 1200 7200 43200 403200 In series II, if ‘x’ is the wrong term, then find which of the following statements(s) are true: I.  X – 325 is a perfect cube. II.  X/800 is a factor 6 and 9 III.  x/27 is a perfect square
    A Only I Correct Answer Incorrect Answer
    B Only I and III Correct Answer Incorrect Answer
    C Only II and III Correct Answer Incorrect Answer
    D All I, II and III Correct Answer Incorrect Answer
    E Only I and II Correct Answer Incorrect Answer

    Solution

    Series II: 20 x 3 = 60 60 x 4 = 240 240 x 5 = 1200 1200 x 6 = 7200 7200 x 7 =  50400 50400 x 8 = 403200 The wrong number is 43200 For statement I:  X = 43200 43200 – 325 = 42875 35 = 3√42875 – which is a perfect cube. Thus, the statement I follow. For statement II: 43200/800 = 54 It is a factor of both 6 & 9. Thus, statement II follows. For statement III: 43200/27 = 1600 √1600 = 40 Thus, statement III follows.

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