CAT 2003 Slot 2QA Question 23

Solving InequalitiesEasy

A real number x satisfying 1-1n<x3+1n, for every positive integer n, is best described by:

Answer & solution

Correct answer: 0 < x &le; 4

  • A

    1 < x < 4

  • B

    1 < x ≤ 3

  • 0 < x ≤ 4

  • D

    1 ≤ x ≤ 3

Solution

(1-1n)<x(3+1n), wher n is a positive integer

If n = 1, then 0 < x ≤ 4

As the value of n increases from 1 to infinity, the range of x approaches (1 < x ≤ 3).

So, the lower limit of x increases from almost 0 (to almost 1), while the higher limit decreases from 4 (to 3).

Thus, the lowest possible limit of x will be > 0 and the highest possible limit will be ≤ 4.

∴ For all range of n, 0 < x ≤ 4

Hence, option (c).

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CAT 2003 Slot 2 QA Q23: A real number x satisfying 1 - 1 n &#60; x &#8804; 3 + 1 n , for every positive integer n, is best described b — Solution | TheCATExam