Madhu is 13th from the end, meaning there are 12 girls behind her.
There were thrice as many in front of her as there were behind:
Girls in front of Madhu =3×12=36
Total number of girls in the column:
Total =girls in front+Madhu+girls behind
Total =36+1+12
Total =49 girls
Madhu's position from the front:
Position from front =36+1=37
So Madhu is 37th from the front.
The 5th girl from the front is at position 5.
Madhu is at position 37.
Number of girls between them =37−5−1
Number of girls between them =31
The "−1" accounts for not counting either the 5th girl or Madhu herself.
Therefore, there are 31 girls between Madhu and the fifth girl from the front.