How long will a man take to go, walking at 13.2 km/h , round a circular garden of 700 m radius ?

Options

A. 12 minute
B. 30 minute
C. 20 minute
D. none of these

Answer

To solve the problem of how long it will take a man to walk around a circular garden with a radius of 700 meters at a speed of 13.2 km/h, we can follow these steps:

### Step 1: Calculate the Circumference of the Circular Garden
The formula for the circumference (C) of a circle is given by:
\[ C = 2 \pi r \]
where \( r \) is the radius.

Given:
- Radius \( r = 700 \) meters

Calculating the circumference:
\[ C = 2 \times \pi \times 700 \]
Using \( \pi \approx 3.14 \):
\[ C \approx 2 \times 3.14 \times 700 \]
\[ C \approx 4398 \text{ meters} \]

### Step 2: Convert the Speed from km/h to m/s
To find the time taken, we need to convert the speed from kilometers per hour to meters per second. The conversion factor is:
\[ 1 \text{ km/h} = \frac{1000 \text{ meters}}{3600 \text{ seconds}} \]
So, to convert 13.2 km/h to m/s:
\[ \text{Speed in m/s} = 13.2 \times \frac{1000}{3600} \]
\[ \text{Speed in m/s} = 13.2 \times \frac{5}{18} \]
\[ \text{Speed in m/s} = 3.67 \text{ m/s} \]

### Step 3: Calculate the Time Taken to Walk Around the Garden
The time taken (t) can be calculated using the formula:
\[ t = \frac{\text{Distance}}{\text{Speed}} \]

Substituting the values:
\[ t = \frac{4398 \text{ meters}}{3.67 \text{ m/s}} \]
Calculating the time:
\[ t \approx 1200 \text{ seconds} \]

### Step 4: Convert Time from Seconds to Minutes
To convert seconds into minutes:
\[ \text{Time in minutes} = \frac{1200 \text{ seconds}}{60} \]
\[ \text{Time in minutes} = 20 \text{ minutes} \]

### Final Answer
The man will take approximately **20 minutes** to walk around the circular garden.

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