Step 1: Extract all clues
We are told:
[(i)] The fare for the train between Chennai and Pune is \rupee 1650
[(ii)] Taj Mahal Express runs between Delhi and Mumbai
[(iii)] Fare for Bengaluru–Agra train is \rupee 750 less than Taj Mahal Express
[(iv)] Fare for Rajdhani Express is \rupee 150 less than Taj Mahal Express
Step 2: Assign train identities and equations
Let us assume:
\[
\text{Fare of Taj Mahal Express} = x
\]
Then:
Bengaluru–Agra train fare = \( x - 750 \)
Rajdhani Express fare = \( x - 150 \)
Only one of the above trains can be Chennai–Pune, with fare \rupee 1650.
Try assigning:
\[
x - 750 = 1650 \Rightarrow x = 2400
\]
Then:
\[
\text{Taj Mahal Express} = 2400, \quad \text{Rajdhani} = 2250, \quad \text{Shatabdi} = 1650
\]
Now check if the assignments match the cities:
Taj Mahal = Delhi–Mumbai (✓)
Then, Bengaluru–Agra must be Shatabdi (✓)
Chennai–Pune must be the remaining → Rajdhani (✓)
Thus,
\[
\text{Fare of Shatabdi Express} = \boxed{\rupee 1800}
\]