hideyoshi
If \(x,y,b\) and \(t\) are all positive integers, \(x = \frac{y}{5} + 2\), and \(t = \frac{b}{7} + 4\), is \(b(t^{xy})\) an even number?
1). \(3.5t - 2\) is even
2). \(\frac{b}{t}\) is even
When you specify the tag for source of "source-other please specify", make sure to specify the source.x=y/5 +2,
t=b/7 + 4,
is \(b(t^{xy})\) = even ?
Per statement 1, 3.5t-2 = even ---> 7t/2-2=even ---> 7t/2 = even +2 = even ----> 7t = even*2 = even --->
t has to be even Also, from the given statements, t=b/7 + 4 ----> 7t=b+28 ---> even - 28 = b ----> b = even . Thus for whatever values of x,y, \(bt^{xy}\) = even . Thus this statement is sufficient.
Per statement 2, b/t=even ---> 2 cases possible (think of 6/3 or 4/2)
case 1: b=even, t=odd
case 2: b = even, t = even
Thus, in either of the 2 cases, b = even and hence for whatever values of x,y, \(bt^{xy}\) = even . Thus this statement is sufficient.
Both statements are sufficient individually, making D as the correct answer.