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NumberProperties

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Source: — Data Sufficiency |

by neerajkumar1_1 » Wed Oct 06, 2010 8:33 pm
given:
root(x)=y
Find: y^3

first, we can find y, as soon as we have a value for x...

lets start with the easy statement
statement2)

x^3= 8
Hence we have a unique value for x = 2... so we can find y
Sufficient

Statement 1)
x = y^x

substituting value of x in equation : root(x) = y

y^(x/2) = y
since bases are same... we can equate the exponents..

x/2=1
x=2
again.. we can get the value for y..
sufficient..

IMO: D
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by ramannjit » Wed Oct 06, 2010 9:36 pm
neerajkumar1_1 wrote:given:
root(x)=y
Find: y^3

first, we can find y, as soon as we have a value for x...

lets start with the easy statement
statement2)

x^3= 8
Hence we have a unique value for x = 2... so we can find y
Sufficient

Statement 1)
x = y^x

substituting value of x in equation : root(x) = y

y^(x/2) = y
since bases are same... we can equate the exponents..

x/2=1
x=2
again.. we can get the value for y..
sufficient..

IMO: D
Thanks Neeraj for explaination!
Ramannjit
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