A car driver leaves Bangalore at 8:30 AM and expects to reach a place 300 km away at 12:30 PM. At 10:30 AM he finds that he has covered only 40% of the distance. By how much must he increase the speed of the car to reach on scheduled time? MCQ with Answer and Explanation
A car driver leaves Bangalore at 8:30 AM and expects to reach a place 300 km away at 12:30 PM. At 10:30 AM he finds that he has covered only 40% of the distance. By how much must he increase the speed of the car to reach on scheduled time?
A. 35 km/h
B. 30 km/h
C. 20 km/h
D. 25 km/h
Answer: Option B
Solution (By JKSSB Mock Tests)
Total time available = 4 hours. At 10:30 AM (after 2 hours), distance covered = 40% of 300 = 120 km. Remaining distance = 180 km. Remaining time = 12:30 PM - 10:30 AM = 2 hours. Required speed = 180 / 2 = 90 km/h. Original speed = 120 / 2 = 60 km/h. Increase in speed = 90 - 60 = 30 km/h.
Explanation:
New speed = 3/5 of normal speed => New time = 5/3 of normal time. Difference = 2/3 of normal time = 20 minutes. Normal time = (20 * 3) / 2 = 30 minutes.
Two marathoners run a long stretch. The winner finishes in 50 minutes while the second runner takes 55 minutes. By what percentage is the winner's speed higher than the runner-up's speed?
Explanation:
Since distance is constant, speed is inversely proportional to time. Ratio of times Winner:Runner-up = 50:55 = 10:11. Ratio of speeds Winner:Runner-up = 11:10. Speed excess percentage = ((11 - 10) / 10) * 100 = 10%.
No comments yet. Be the first to start the discussion!