For which positive integers n does the inequality 3ⁿ exceed n³?
n ≥ 2
n ≥ 3
n ≥ 4
n < 4
Correct answer: n ≥ 4
Solution
Check: n=1 (3>1) and n=2 (9>8) hold, n=3 gives 27=27 (not strictly greater) so it fails, and for n>=4 (81>64, ...) it always holds. The condition guaranteeing 3^n>n^3 for all such n is n>=4; 'n<4' is false since n=3 fails.