Panchayat solves the wrong problem

In Panchayat Season 1 Episode 7 Ladka Tez Hai Lekin…, at around 17:00, Pradhan asks Abhishek to solve problem 42.

42. A takes 5 days more than B to do a certain job and 9 days more than C.
    A and B together can do the job in the same time as C.
    How many days would A take to do it?

    (a) 16 days
    (b) 18 days
    (c) 15 days
    (d) 20 days

The correct answer is (c) 15 days. But interestingly, ChatGPT got it wrong the first time too. It said (a) 15 days instead of (c) 15 days, and required a fact-check to correct itself.

But Abhishek’s steps have nothing to do with the problem - he proceeds to solve a completely different problem and ends up with the supposedly correct answer of 37/23.

(ii)

Qty of x in container (100 l) = 40 lts
Qty of y in the container of 100 ltr = 60 ltr

Qty of Milk in final Mix = 100 × 3/4 = 75 ltr
Qty of water in final Mix = 100 − 75 = 25 ltr

[crossed / scratched working]

x = 40 × 2/3 , 40 × 1/3 = 80/3 , 40/3   [circled]

Qty of Milk & water in 60 ltr of Mix

y = (60 × a)/(a + 2) , (60 × 2)/(a + 2)
  = 60a/(a + 2) , 120/(a + 2)

Now, the problem I’m trying to solve is, which of these made the bigger mistake:

• Abhishek, who solved a different problem
• ChatGPT, who got the answer right but the option wrong
• The writers of the show, who failed to correct this obvious error