There are 1296 possible outcomes [1111, 1112, 1113, 1114, ....6664, 6665, 6666].
Of these, 171 have 2 or more 6's.
The probability is 171/1296 = 0.13194
Rounded to the nearest tenth of a percent, that is P=13.2%.
Probability of getting a 6 when a dice is thrown once = 1/6.
Probability of getting 6 k times when thrown n times = (n C k)*(pk)*(1-p)n-k
Here, n=4 and k=2,3, 4
(4 C 2)*(1/6)2(5/6)2 + (4 C 3)*(1/6)3(5/6)1 + (4 C 4)*(1/6)4
0.115740741 + 0.015432099 + 0.000771605
0.131944444