Concept:
Profit in a partnership is divided in the ratio of capital invested multiplied by the duration for which that capital remained invested.
Step 1: Calculate P's capital-months.
For first 3 months,
\[
60000\times3=180000
\]
After withdrawing ₹20000, capital becomes ₹40000 for remaining 9 months.
\[
40000\times9=360000
\]
Therefore,
\[
P=180000+360000
\]
\[
=540000
\]
Step 2: Calculate Q's capital-months.
For first 3 months,
\[
45000\times3=135000
\]
After adding ₹15000, capital becomes ₹60000 for remaining 9 months.
\[
60000\times9=540000
\]
Thus,
\[
Q=135000+540000
\]
\[
=675000
\]
Step 3: Calculate R's capital-months.
R joins after \(3+5=8\) months.
Therefore R remains for
\[
12-8=4 \text{ months}
\]
Hence,
\[
R=90000\times4
\]
\[
=360000
\]
Step 4: Find the profit sharing ratio.
\[
P:Q:R
=
540000:675000:360000
\]
Dividing by 45000,
\[
12:15:8
\]
Total ratio units
\[
=12+15+8
\]
\[
=35
\]
Step 5: Calculate the difference between P's and R's profits.
Difference in ratio units
\[
=12-8=4
\]
Therefore difference in profit
\[
=\frac{4}{35}\times32200
\]
\[
=4\times920
\]
\[
=3680
\]
Hence the required difference is
\[
\boxed{₹3680}
\]