okay lets change the question a bit that won't matter b'coz the question will be same after all. Instead of finding probability that 3 dices will land with a 3 facing up, find the probability that the 3 dices will land with same no facing up.
S=sample space
n(S)=number of total outcome of sample space=6×6×6=216 {since there are 3 dices}
E=events that all 3 dices land with a same no facing up
n(E)=no of ways in which the dice will have same no=6
{b'coz at a time ,;one face with same no will be facing up and in a dice there is 6 faces...so at 6 different favourable ocassion there are 6 ways that the dice will have same no}
then probability of getting same no is,
P(E)=n(E)/n(S)
=6/216 = 1/36 ANS...