GmatKiss wrote:If b is an integer, is root(a^2+b^2) an integer?
(1) a2 + b2 is an integer.
(2) a² + b² = (√3)² + 1² = 4.
Statement 1: a² + b² is an integer.
Let a=√3 and b=1 so that a² + b² = (√3)² + 1² = 4.
Then √(a²+b²) = √(√3² + 1²) = 2.
Let a=1 and b=1 so that a² + b² = 1² + 1² = 2.
Then √(a²+b²) = √(1² + 1²) = √2.
INSUFFICIENT.
Statement 2: a² - 3b² = 0.
Substituting a²=3b² into √(a²+b²):
√(a²+b²) = √(3b²+b²) = √(4b²) = 2b, which must be an integer since b is an integer.
SUFFICIENT.
The correct answer is
B.
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