Question

Excluding the halts, the speed of the bus is 50 km/ hr and including the halts it is 40 km/hr. For how many minutes does the bus stop per hour?

• A. 12
• B. 10
• C. 15
• D. 11

Answer 1

The Correct Option is A

Let's solve the problem step by step.
Given:
- Speed excluding halts: 50 km/hr
- Speed including halts: 40 km/hr
Let \( t \) be the time the bus is running (in hours) and \( s \) be the time the bus is stopped (in hours).
Since the bus stops every hour, the total distance covered in 1 hour, including halts, is equal to the distance covered without halts minus the distance lost during the halts.
The distance covered in \( t \) hours at a speed of 50 km/hr is:
\[ \text{Distance} = 50t \]
The distance covered in 1 hour at a speed of 40 km/hr is:
\[ \text{Distance} = 40 \times 1 = 40 \text{ km} \]
Equating the two distances, we get:|
\[ 50t = 40 \]
\[ t = \frac{40}{50} = 0.8 \text{ hours} \]
The bus is running for 0.8 hours, which means it stops for:
\[ 1 - 0.8 = 0.2 \text{ hours} \]
To convert the stopping time to minutes:
\[ 0.2 \text{ hours} \times 60 \text{ minutes/hour} = 12 \text{ minutes} \]
Therefore, the bus stops for:
Answer: A (12 minutes)