A die is rolled 3 times. If getting six is considered as success. The probability of atleast 2 successes is

Given die is rolled 3 times

 from the given data, there are four ways by which success can be achived.

                                first throw            second throw           third  throw

Case (i)                        6                           6                          { 1, 2, 3, 4, 5,  }

Case (ii)             { 1, 2, 3, 4, 5 }                6                           6

Case (iii)                      6                  { 1, 2, 3, 4, 5 }               6

Case (iv)                      6                           6                           6

P (success) $=\left(\frac{1}{6}\times \frac{1}{6}\times \frac{5}{6}\right)+\left(\frac{5}{6}\times \frac{1}{6}\times \frac{1}{6}\right)+\left(\frac{1}{6}\times \frac{5}{6}\times \frac{1}{6}\right)+\left(\frac{1}{6}\times \frac{1}{6}\times \frac{1}{6}\right)$

                      $$\begin{gathered} =\frac{5+5+5+1}{216} \\ =\frac{16}{216} \\ =\frac{2}{27} \end{gathered}$$