Let's solve the problems one by one:

1. Robyn's average time for a 200 m sprint

Robyn’s times are 50, 54, 51, and 53 seconds. To calculate the average: $\text{Average time} = \frac{50 + 54 + 51 + 53}{4} = \frac{208}{4} = 52 \text{ seconds.}$ Answer: 52 seconds.

2. Playground usage

Two-fifths of Pete Hill Public School’s playground is for soccer, and the playground area is 3 hectares. The area for soccer: $\text{Area for soccer} = \frac{2}{5} \times 3 = 1.2 \text{ hectares.}$ The remaining area for other sports: $\text{Remaining area} = 3 - 1.2 = 1.8 \text{ hectares.}$ Answer: 1.8 hectares.

3. Shane's rows of circles

Shane drew 32 circles in the first row, with each successive row containing half as many circles as the previous row. He drew 6 rows. The total number of circles is: $\text{Circles per row: } 32, 16, 8, 4, 2, 1.$ $\text{Total circles} = 32 + 16 + 8 + 4 + 2 + 1 = 63.$ Answer: 63 circles.

4. Amanda's leaflet distribution

Amanda wants 30 people to respond, and 1 in 5 responds. The number of leaflets she must distribute: $\text{Leaflets needed} = 30 \times 5 = 150.$ Answer: 150 houses.

Do you want any detailed explanations or have further questions? Here are related questions for further exploration:

1. How can we determine the median sprint time for Robyn's 200 m races?
2. What fraction of the playground is left unused for sports activities?
3. What would be the total number of circles if Shane added another row?
4. How would the number of leaflets change if Amanda's response rate improved to 1 in 4?
5. Can you identify a general formula for Shane’s rows of circles using powers of 2?

Tip: Always break complex problems into smaller, manageable steps to ensure accuracy and clarity.