max value of X

[Claret]

If X^4+Y^4=100, then the greatest possible value of X is between:
A. 0 and 3
B. 3 and 6
C. 6 and 9
D. 9 and 12
E. 12 and 15

Ans B

IMO it shud be A

any insights?

[ssmiles08]

If you make y = 0, to maximize x,
x will be a little bigger than 3 so it falls under [3 6]

(B)

[Claret]

yep got it ! thanks!