Sometime we are caught up with easy but lengthy problems. In the series of Cheeky approach to few lengthy problems, I am recommnding few common sense approaches.
Enjoy!
Q. What is the value of x^3+y^3+z^3 ? if x+y+z = 6 and xy+yz+zx = 11.
A.24
B.36
C.54
D.121
E.25
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Just analyse x+y+z = 6 and xy+yz+zx = 11. Try to fit in few small +ive integers for x, y & z .
Say... x=y=z=2. But this does not satisfy xy+yz+zx = 11. Hence rejected.
Just by hit & trial, lets see x=1, y=2 & x=3 satisfies xy+yz+zx = 11. Hence solution is B.
Enjoy!
Q. What is the value of x^3+y^3+z^3 ? if x+y+z = 6 and xy+yz+zx = 11.
A.24
B.36
C.54
D.121
E.25
----------------------------------------------------------------------------
Just analyse x+y+z = 6 and xy+yz+zx = 11. Try to fit in few small +ive integers for x, y & z .
Say... x=y=z=2. But this does not satisfy xy+yz+zx = 11. Hence rejected.
Just by hit & trial, lets see x=1, y=2 & x=3 satisfies xy+yz+zx = 11. Hence solution is B.
Shalabh Jain,
e-GMAT Instructor
e-GMAT Instructor
