dear dashmesh , here is the simple method to solve such type of problems ....
distance travelled in n seconds (Sn) = gn2/2
distance travelled in (n-1) seconds (Sn-1) = g(n-1)2/2
distance travelled in nth second =  Sn - Sn-1
Snth = g/2 [ n2 - (n-1)2 ]
      = g/2 [ (2n-1) ]  .......................1
this is the formula for finding distance travelled in nth second....
distance travelled during fifth second is S5th at n = 5
 S5th = g/2[ (2*5-1)] = 9g/2                 (g  = 10m/s2)
                               =45m   
 
approve my ans if u like it
						

							
Here's a formula for the distance traversed by the body in nth second:
 
Snth = u + a/2 (2n-1)
u = intial velocity of the body,
a = acceleration of the body (with proper algebric signs)
you can also apply the same formula for displacement by using vector addition and substraction formula.

						

							
 
Snth = u + a/2 (2n-1)
by calculas method
						

							
 
Snth = u + a/2 (2n-1)
by calculas method
						

							
 
Snth = u + a/2 (2n-1)
by calculas method
						

							
 
Snth = u + a/2 (2n-1)
by calculas method
						

							
 
Snth = u + a/2 (2n-1)
by calculas method
						

							
 
Snth = u + a/2 (2n-1)
by calculas method
						

							
 
Snth = u + a/2 (2n-1)
by calculas method