probability is 1/3..
Solution:- there are 6 cases P(x1>x2>x3), P(x1>x3>x2), P(x2>x1>x3), P(x2>x3>x1), P(x3>x2>x1), P(x3>x1>x2).
All cases are equally likely and hence P(x1) being largest is P(x1>x2>x3) or P(x1>x3>x2).
Hence, P(x1 being largest)=2/6=1/3