IF THREE SIX FACED FAIR DICE ARE THROWN TOGETHER THEN PROBABILITY THAT SUM OF THE NUMBERS APPEARING ON THE DICE IS K(3<=K<=8)

the total no of possibilities=216

no of favourable outcomes for k ={111......116,121......125,131....134,141....143,151,152,161}

n(k)=21

p(k)=21/216

=7/72

The probability is: 7/27.