Multiple choice

Renu travels for 7 hours at the speed of 40 km/hr and for 5 hr at the speed of 60 km/hr. She has covered 4/5 of the total distance at the end of 12 hr. At what average speed should she travel to cover the remaining distance in 5 hrs. रेनू 7 घण्टे 40 किमी/घं. की चाल से और 5 घण्टे 60 किमी/घं. की चाल से चलती है। कुल 12 घण्टे पूरे होने पर वह कुल दूरी का 4/5 भाग तय कर लेती है। वह किस औसत चाल से बची हुई दूरी तय करे कि उसे 5 घण्टे लगें?

  1. 45 km/hr

  2. 55 km/hr

  3. 35 km/hr

  4. 29 km/hr
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Distance covered in first 7 hours = 7 × 40 = 280 km. Distance covered in next 5 hours = 5 × 60 = 300 km. Total distance in 12 hours = 580 km, which is 4/5 of total distance. So total distance = 580 × 5/4 = 725 km. Remaining distance = 725 - 580 = 145 km. To cover 145 km in 5 hours: average speed = 145/5 = 29 km/hr. Option A (45), B (55), and C (35) are all too high.

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