Question

On a 100 kilometre track A train travels the first 30 km at a uniform speed of 30 km per hour. how

much fast must the train travel the next 70 kilometre so as to average 40 kilometre per hour for the

entire trip?

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Answer 1

Answer:   Speed for 70 km is 46.6 km/hr

Explanation:    LET'S START ITS SOLUTION ....↓↓↓↓

SO.....

1st Distance D1  = 30 km

2nd Distance D2 = 70 km

The time taken to travel 30 km (D1) is 30 km/hr.

The average speed to travel the whole 100 km is average 40km/hr.

Average speed = (Distance 1+Distance 2)/(Time 1+ Time 2)  

⇒                   40 = 100/(1+Time 2)

⇒                   40( 1 + time 2) = 100

⇒                    40 + 40 T2  

⇒                   40 T2  = 100  - 40

⇒                  40 T2 = 60

= 100

 ⇒              T2 = 60 / 40 = 1.5 km/hr

 Speed for 70 km = Distance 2 /Time 2

            Speed = 70/1.5 = 46.6

    Speed for 70 km is 46.6 km/hr

Höpe you understand the solution

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