Solution:

=> x = 0.3178178178… ….(i)
Multiplying both sides of (i) by 10, we get
10x = 3.178178… ….(ii)
Multiplying both sides of (i) by 10000, we get
10000x = 3178.178… ….(iii)
Subtracting (ii) from (iii), we get
9990x = 3175
=> x = 3175/9990 = 635/1998