If W=x^4 + y^4 = 100, then the greatest possible value of x is between  Pick:
A) 0 and 3
B) 3 and 6
C) 6 and 9
D) 9 and 12
E) 12 and 15
My attempt:   If W=x^4+y^4=100, then the greatest possible value of x would be when y is minimum.   Let y^4 be 0. Now x^4 = 100. x should be definitely greater than 3 but less than 4. The only option that fits this range is 3 and 6   Hence answer is --   b) 3 and 6.
<result>B</result>
If W=x^4 + y^4 = 100, then the greatest possible value of x is between