Supriya runs a marathon race in 50 minutes at an average speed of 48 km/hr. In…
2024
Supriya runs a marathon race in 50 minutes at an average speed of 48 km/hr. In order to set a national record she need to win the race in 40 minutes. Considering that her speed remain constant, at what minimum speed she should run to set the record ?
- A.
70 km/hr
- B.
60 km/hr
- C.
55 km/hr
- D.
50 km/hr
Attempted by 14 students.
Show answer & explanation
Correct answer: B
Answer: 60 km/hr.
Reason:
Step 1: Convert times to hours. 50 minutes = 50/60 = 5/6 hour; 40 minutes = 40/60 = 2/3 hour.
Step 2: Compute race distance using the original performance: distance = speed * time = 48 km/hr * (5/6) hr = 40 km.
Step 3: Required speed to finish in 40 minutes = distance / time = 40 km / (2/3) hr = 40 * (3/2) = 60 km/hr.
Conclusion: The minimum speed needed to set the record is 60 km/hr.