LUANDATO wrote:Given that a>1 and b>1. Is (a^x)(b^y)<1?
(1) a^(x+y) < 1
(2) b^(x+y) < 1
The OA is E.
Can any expert help me with this DS question please? Thanks.
(1) a^(x+y) < 1
Case 1: Say a = 2, b= 3, x = 1, and y = -2. This ensures that a^(x+y) = 2^(1 - 2) = 2^(-1) = 1/2 < 1.
At these values, (a^x)(b^y) = (2^1)(3^(-2)) = 2*3^-2 = 2/9 < 1. The answer is yes.
Case 2: Say a = 10, b= 3, x = 1, and y = -2. This ensures that a^(x+y) = 10^(1 - 2) = 10^(-1) = 1/10 < 1.
At these values, (a^x)(b^y) = (10^1)(3^(-2)) = 10*3^-2 = 10/9
> 1. The answer is No.
(2) b^(x+y) < 1
Both the cases discussed above are applicable here too. Insufficient.
(1) & (2) b^(x+y) < 1
As stated that both the cases discussed above are applicable here too. Insufficient.
The correct answer:
E
Hope this helps!
-Jay
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