Competititve Exams Materials
(Q) Find the following problem ?
3^( x – y )=27 and 3^( x + y )=243, then x is ?
A) 4
B) 6
C) 8
D) 12
Explanation :
3^( x – y) = 27
=> 3 (x – y) = 3^3
=> x – y = 3 3^( x + y) = 243
=> 3^(x + y) = 3^5
=> x + y = 5 Adding these two equations,
we get 2x = 8 => x = 4
A) 4
B) 6
C) 8
D) 12
View Answer
A) 4Explanation :
3^( x – y) = 27
=> 3 (x – y) = 3^3
=> x – y = 3 3^( x + y) = 243
=> 3^(x + y) = 3^5
=> x + y = 5 Adding these two equations,
we get 2x = 8 => x = 4
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Aptitude : Surds and Indices
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