A driver of an auto rickshaw sees a lorry 60 m ahead of him. After 30 seconds the lorry is 90 m behind. If the speed of the auto rickshaw is 38 km/hr. then what is the speed of the lorry?

A driver of an auto rickshaw sees a lorry 60 m ahead of him. After 30 seconds the lorry is 90 m behind. If the speed of the auto rickshaw is 38 km/hr. then what is the speed of the lorry?

(A) 23 km/hr

(B) 25 km/hr

(C) 20 km/hr

(D) 18 km/hr

Answer: (C) 20 km/hr

Relative speed =   Total distance/ Total time = (60 + 90)/30   = 5 m/s = 5 × 18/5        = 18 kmph

Now relative speed = speed of auto rickshaw – speed of lorry

or, 18 = 38 – speed of lorry

So, Speed of lorry = 38 – 18 = 20 km/h
A driver of an auto rickshaw sees a lorry 60 m ahead of him. After 30 seconds the lorry is 90 m behind. If the speed of the auto rickshaw is 38 km/hr. then what is the speed of the lorry? A driver of an auto rickshaw sees a lorry 60 m ahead of him. After 30 seconds the lorry is 90 m behind. If the speed of the auto rickshaw is 38 km/hr. then what is the speed of the lorry? Reviewed by Admin on 8:34 AM Rating: 5

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