Question : A man cycles at the speed of 8 km/h and reaches the office at 11 am and when he cycles at the speed of 12 km/h, he reaches the office at 9 am. At what speed should he cycle so that he reaches his office at 10 am?
Option 1: 9.6 km/h
Option 2: 10 km/h
Option 3: 11.2 km/h
Option 4: cannot be determined
Correct Answer: 9.6 km/h
Solution :
Given: First speed = 8 km/h and second speed = 12 km/h
The starting time will be the same in both conditions.
Distance travelled by first speed in 2 hours,
We know that, Distance = Speed $\times$ Time
⇒ Distance = 8 $\times$ 2 km
$\therefore$ Distance = 16 km
Now, the time is taken by second speed to travel a distance of 16 km,
Time = $\frac{\text{distance}}{\text{second speed - first speed}}$
Time = $\frac{16}{12 -8}$ = 4 hour
So, the total time taken by second speed = 4 h
$\therefore$ total distance = 4 $\times$ 12 = 48 km
Starting time to travel at second speed = 9 am − 4 hrs = 5 am
According to the question,
At 10 am, the required time to reach the office = 10 am − 5 am = 5 hrs
So, required speed = Total Distance / Time
⇒ Required speed = $\frac{48}{5}$ = 9.6 km/h
Hence, the correct answer is 9.6 km/h.
Related Questions
Know More about
Staff Selection Commission Sub Inspector ...
Result | Eligibility | Application | Selection Process | Cutoff | Admit Card | Preparation Tips
Get Updates Brochure
Your Staff Selection Commission Sub Inspector Exam brochure has been successfully mailed to your registered email id “”.
