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CAT 2006 — QA Question 7

IndicesEasy

What are the values of x and y that satisfy both the equations?

20.7x . 3−1. 25y = 8627

40.3x . 90.2y = 8 . (81)1/5

Answer & solution

  • A

    x = 2, y = 5

  • B

    x = 2.5, y = 6

  • C

    x = 3, y = 5

  • D

    x = 3, y = 4

  • x = 5, y = 2

Solution

The fastest way to solve this sum is by substituting the values of x and y from the options.

For x = 5 and y = 2, the first equation becomes

20.7x × 3−1.25y  = 20.7× 5 × 3−1.25 × 2

              = 27/2 × 3−5/2

             = 8627

These values of x and y satisfy the second equation also.

Hence, option (e).

CAT 2006 QA Q7: What are the values of x and y that satisfy both the equations? 2 0.7x . 3 −1. 25y = 8 6 27 4 0.3x . 9 0 — Solution | TheCATExam