Interpret the path

The person moves along the path $O \to P \to Q \to O$.

From the figure description and statement, the curved part $PQ$ is a semicircle of radius $200\,\text{m}$, with $O$ as the centre of the park and $OP$ and $QO$ as radii.

Find total distance travelled

Radius $r = 200\,\text{m}$

• Straight path $OP = 200\,\text{m}$
• Curved path $PQ$ is a semicircle: $\text{Length of semicircle} = \pi r = 3.14 \times 200 = 628\,\text{m}$
• Straight path $QO = 200\,\text{m}$

So total distance is $200 + 628 + 200 = 1028\,\text{m}$

Convert total time into seconds

Given time $= 3\,\text{min}\,58\,\text{s}$ $3\times 60 + 58 = 180 + 58 = 238\,\text{s}$

Compute average speed

$\text{Average speed} = \frac{\text{Total distance}}{\text{Total time}} = \frac{1028}{238}$

$\frac{1028}{238} \approx 4.32\,\text{m s}^{-1}$

Integer answer

Since this is an integer-type question, the required answer is $\boxed{4}$

Comparison with stored answer

Stored correct answer is $3$, but the calculated average speed is about $4.32\,\text{m s}^{-1}$, so the integer answer should be $4$, not $3$.