3) Approximately 120/1000(Depending on the randomization)

var('x') x=0 for y in range (1000): F=matrix([[randint(0,1) for i in range(1,11)] for j in range(1,11)]) if (F.echelon_form()==identity_matrix(10)): x=x+1 show(x/1000)

3) Approximately 120/1000(Depending on the randomization)

var('x')
x=0
for y in range (1000):
    F=matrix([[randint(0,1) for i in range(1,11)] for j in range(1,11)])
    if (F.echelon_form()==identity_matrix(10)):
        x=x+1
show(x/1000)
show(x/1000)