RRB JE 2015 Paper

Question 139

If $$2^{2n - 1} = \frac{1}{8^{n - 3}}$$, then the value of 'n' is:

Solution

Given that $$2^{2n - 1} = \frac{1}{8^{n - 3}}$$

=>  $$2^{2n - 1} = 8^{3 - n}$$

=>  $$2^{2n - 1} = 2^{9 - 3n}$$

As the bases are equal, their powers are equal

=> 2n-1 = 9-3n

=> 5n=10

=> n=2

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