Step 1: Recall a shortcut for this kind of problem.
Extra simple interest earned only depends on the principal, the time, and how much the rate increased, since the original rate cancels out. The shortcut is: Extra Interest $= \frac{P \times \text{Time} \times \text{Rate increase}}{100}$.
Step 2: Plug in the known numbers.
Time = 3 years, Rate increase = 2%, Extra Interest = Rs. 360. So $360 = \frac{P \times 3 \times 2}{100} = \frac{6P}{100}$.
Step 3: Solve for P.
$6P = 360 \times 100 = 36000$, so $P = \frac{36000}{6} = 6000$.
Step 4: Check with a sample rate.
Try an original rate of 5%: interest at 5% for 3 years on Rs. 6000 is $\frac{6000 \times 3 \times 5}{100} = 900$. At 7% (2% higher), interest is $\frac{6000 \times 3 \times 7}{100} = 1260$. The difference is $1260 - 900 = 360$, which matches, confirming P = 6000 regardless of the original rate.
Final Answer:
Rs. XYZ equals Rs. 6000.
\[ \boxed{Rs.\ 6000} \]