The average response time depends upon the value of x
if x < 3
then the order is x,3,5,6
if the value of x >3 and x < 5
the the order is 3,x,5,6
if the value of x > 5 and x < 6
then the order is 3,5,x,6,
if the order > 6
then the order is
3,5,6,x
For the second question it will be S1---S2---S3---S4---S5 OR S1---S3----S2----S4----S5