yezz wrote:

Given that a>1 and b>1. Is (a^x)(b^y)<1?

(1) a^(x+y) < 1

(2) b^(x+y) < 1

St1:

Given: a^(x+y) < 1 => a^x * a^y < 1

St1 could be true in the following 3 cases:

a) x<=0 & y<=0 ..............

(They cannot be both zero at the same time)-> (a^x)(b^y)<1 is TRUE

b) x<0, y>=0 & y < Abs(x), where Abs(x) means absolute value of x

-> Whether (a^x)(b^y)<1 is true or not depends on the relation between a & b.

c) y<0, x>=0 & x < Abs(y), where Abs(y) means absolute value of y

-> Whether (a^x)(b^y)<1 is true or not depends on the relation between a & b.

=> NOT SUFFICIENTSt2:

By same reasoning,

=> NOT SUFFICIENTSt1 & St2 Together:

Since we still donot know and cannot deduce any relation between a & b, we cannot conclude anything.

=> NOT SUFFICIENTANS: E _________________

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