Madhu is thirteenth from the end in a column of girls. There were thrice as many in front of her as there were behind. How many girls are there…

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 $= 3 \times 12 = 36$=3×12=36

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Total number of girls in the column:

Total $= \text{girls in front} + \text{Madhu} + \text{girls behind}$=girls in front+Madhu+girls behind

Total $= 36 + 1 + 12$=36+1+12

Total $= 49$=49 girls

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Madhu's position from the front:

Position from front $= 36 + 1 = 37$=36+1=37

So Madhu is 37th from the front.

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The 5th girl from the front is at position 5.

Madhu is at position 37.

Number of girls between them $= 37 - 5 - 1$=37−5−1

Number of girls between them $= 31$=31

The "$-1$−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.