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if x,y and z are integers, is x(y^2 + z^3) even ?

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Source: — Data Sufficiency |

by scoobydooby » Wed Mar 25, 2009 4:56 am
is x(y^2 + z^3) even ?

stmt 1) x is odd
case 1: y and z even=>O(E+E)=E
case 2: y and z odd=> O(O+O)=O*E=E
case 3: x even, y odd or vice versa=> O(O+E)=O*O=O
not sufficient


stmt 2) xyz is odd
=> x, y and z all are odd (if any one was even then xyz would have been even)
O(O+O)=O*E=E
sufficient

hence B
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by sanjay_dce » Wed Mar 25, 2009 8:38 am
from stm2 we know that all x, y ,z are odd hence B
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by quocbao » Fri Mar 27, 2009 9:51 am
Can you explain why x,y,z is odd from statement 2 ?

We can also have x is odd, y z is even also ?
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by goelmohit2002 » Fri Mar 27, 2009 10:19 am
quocbao wrote:Can you explain why x,y,z is odd from statement 2 ?

We can also have x is odd, y z is even also ?
if any of x, y or z are even, then the product xyz cannot be odd....
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