x^2+y^2>100
rephrasing
(x+y)^2-2xy>100
from stmt1,
2xy<100
xy<50
xy can be of any value,so insufficient.
from stmt2,
(x+y)^2>200
The least value (>200) is x+y=14.2
what ever value of x and y,x^2+y^2>100
IMO B
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DS
Source: Beat The GMAT — Data Sufficiency |
x^2 + y^2 = (x + y)^2 - 2xy
St 1 tells us only about 2xy so insuff.
St 2 tells us only about (x+y)^2 so again insuff.
St 1 & 2: tell us about the least value for the first term & greatest value for the 2nd term and hence are sufficient. Hence, C
St 1 tells us only about 2xy so insuff.
St 2 tells us only about (x+y)^2 so again insuff.
St 1 & 2: tell us about the least value for the first term & greatest value for the 2nd term and hence are sufficient. Hence, C
IMO B as well.
x+y > 10sqrt2
If x = y boundary condition, x = y > 5 sqrt2 for which x^2+y^2 always greater than 100.
x+y > 10sqrt2
If x = y boundary condition, x = y > 5 sqrt2 for which x^2+y^2 always greater than 100.
