Answer:
Assuming the repetitive part is 152, i.e. the original repeating decimal is
A=3.152152152....
then
1000A=3152.152152152152....
subtract A
1000A-A=3152.152152....-3.152152152....
999A=3149
A=3149/999=3+152/999=3 152/999
Therefore
3.152152152.... = 3149/999 or 3 152/999