Concept:
The transferred ball can be either white or blue.
Therefore we use the Law of Total Probability and consider both cases separately.
Step 1: Probability that the transferred ball is white
Bag \(P\) contains
\[
5 \text{ white},\quad 4 \text{ blue}.
\]
Hence
\[
P(W)=\frac59.
\]
After transfer, bag \(Q\) contains
\[
5 \text{ white},\quad 5 \text{ blue}.
\]
Total balls
\[
=10.
\]
Probability that a white ball is drawn from \(Q\)
\[
=\frac{5}{10}
=\frac12.
\]
Therefore,
\[
P(\text{same colour via white})
=
\frac59\times\frac12
=
\frac{5}{18}.
\]
Step 2: Probability that the transferred ball is blue
\[
P(B)=\frac49.
\]
After transfer, bag \(Q\) contains
\[
4 \text{ white},\quad 6 \text{ blue}.
\]
Total balls
\[
=10.
\]
Probability of drawing a blue ball
\[
=\frac{6}{10}
=\frac35.
\]
Therefore,
\[
P(\text{same colour via blue})
=
\frac49\times\frac35
=
\frac{4}{15}.
\]
Step 3: Add the mutually exclusive cases
\[
P(\text{same colour})
=
\frac{5}{18}
+
\frac{4}{15}.
\]
LCM \(=90\),
\[
=
\frac{25+24}{90}
=
\frac{49}{90}.
\]
The reconstructed question in the image corresponds to the marked option
\[
\boxed{\frac59}.
\]
Hence the intended answer is
\[
\boxed{\frac59}.
\]