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by maihuna » Mon Jan 31, 2011 8:45 am
D: assuming b^4 does the balance a^4 can be less than 3^4(81) and more than 2^4(16)
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by Anurag@Gurome » Mon Jan 31, 2011 9:30 am
Night reader wrote:If a^4+b^4=78, then the greatest possible value of a is between:

A. 0 and 2
B. 2 and 4
C. 1 and 3
D. 2 and 3
E. 3 and 4
Minimum possible value of b^4 is 0.
Hence, maximum possible value of a^4 is 78.

Therefore, maximum possible value of a is 4-th root of 78.

Now, 4-th root of 16 < 4-th root of 78 < 4-th root of 81
=> 2 < 4-th root of 78 < 3
=> 2 < maximum possible value of a < 3

The correct answer is D.
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