Question
Download Solution PDFA girl goes to school at a speed of 6 km/hr. She comes back with a speed of 18 km/hr. Find her average speed for the whole journey.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven:
Speed of the girl going to school = 6 km/h.
Speed of the girl coming back = 18 km/h.
Formula Used:
Average speed = Total distance travelled/Total Time
Calculation:
Let the distance to school be d km.
Time taken to go to school = d / 6
Time taken to come back = d / 18
Total Distance = d + d = 2d
Total Time = (d / 6) + (d / 18)
Total Time = d(1/6 + 1/18)
Total Time = d(3/18 + 1/18)
Total Time = d(4/18)
Total Time = \( \frac{2d}{9} \)
Average Speed = (2d) / \( \frac{2d}{9} \)
Average Speed = (2d × 9) / 2d
Average Speed = 9 km/h
The average speed for the whole journey is 9 km/h.
Last updated on Jun 2, 2025
-> The Railway Recruitment Board has released the RPF Constable 2025 Response Sheet on 24th March 2025. As per the official notice, the RPF Constable Answer Key will be available from 24th March 2025 to 29th March 2025.
-> The RRB ALP 2025 Notification has been released on the official website.
-> The Examination was held from 2nd March to 18th March 2025. Check the RPF Exam Analysis Live Updates Here.
-> RPF Constable 2025 application status was released in January 20, 2025.