Question

How much time (in minutes) does Simran take to cover a distance of 600 m, if she runs at a speed of 36 km/hr?

• A. 12
• B. 30
• C. 60
• D. 1

Hint:

Speed conversion shortcut: $18 \text{ km/hr} = 5 \text{ m/s}$ $36 \text{ km/hr} = 10 \text{ m/s}$ $54 \text{ km/hr} = 15 \text{ m/s}$ $72 \text{ km/hr} = 20 \text{ m/s}$

Answer 1

The Correct Option is D

Concept: The basic formula is $\text{Time} = \text{Distance} / \text{Speed}$. However, units must be consistent. We must convert speed from km/hr to m/s.

Step 1: Convert Speed to m/s.
To convert km/hr to m/s, multiply by $\frac{5}{18}$. \[ \text{Speed} = 36 \times \frac{5}{18} = 2 \times 5 = 10 \text{ m/s.} \]

Step 2: Calculate time in seconds.
\[ \text{Time (s)} = \frac{\text{Distance}}{\text{Speed}} = \frac{600 \text{ m}}{10 \text{ m/s}} = 60 \text{ seconds.} \]

Step 3: Convert time to minutes.
Since 60 seconds $= 1$ minute, Simran takes 1 minute to cover the distance.