CSASHISHPANDAY wrote:if X & Y are integer is X^7 is greater that 6^Y
1. X^3=-125
2. Y^2=36
Target question:
Is x^7 > 6^y?
Statement 1: x^3 = -125
There's a nice rule that says, "
An odd exponent preserves the sign of the base"
In other words, (any negative number)^(odd integer) = negative number
. . . and (any positive number)^(odd integer) = positive number
So, statement 1 essentially tells us that x must be a negative number. Now, we
could go further and determine that x = -5, but that's not really necessary here. Knowing that x is negative provides enough information to answer our target question with certainty.
First, since x is negative, we know that x^7 must be negative.
Second, we know 6^(any value) will equal a positive number.
So, it must be the case that
Is x^7 is not greater than 6^y?
Statement 1 is SUFFICIENT
Statement 2: y^2 = 36
From this, we can conclude that y = 6 or y = -6.
Let's examine both cases:
case a: y = 6.
In this case, we
cannot determine whether x^7 is greater than 6^y, since we have no idea what x equals.
case b: y = -6.
In this case, we
cannot determine whether x^7 is greater than 6^y, since we have no idea what x equals.
Statement 2 is NOT SUFFICIENT
Answer =
A
Cheers,
Brent
