Comparison of radical values

CMAT 2018 · Quantitative Techniques & Data Interpretation · Easy · Surds and Indices

If x=65x = \sqrt[5]{6} and y=54y = \sqrt[4]{5}, Which of the following is true?

  1. A.

    x>yx > y

  2. B.

    y>xy > x

  3. C.

    x=yx = y

  4. D.

    None

Answer

B

Explanation

LCM of the orders of roots (5 and 4) is 20. x=61/5=(64)1/20=(1296)1/20x = 6^{1/5} = (6^4)^{1/20} = (1296)^{1/20} y=51/4=(55)1/20=(3125)1/20y = 5^{1/4} = (5^5)^{1/20} = (3125)^{1/20}

Since 3125>12963125 > 1296, y>xy > x.

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