Question

on a 60 km track, train travels the first 30km at a uniform speed of 30 km/h.how fast must the train travel the next 30 km so that the average speed is 40 km/h for the entire trip​

Answer 1

Answer:

train should travel at a speed of 50km/hr

Answer 2

★ 60 km/h ✬

Explanation:

Given:

• Total distance (d) is 60 km.
• Speed (v¹) during the first half journey = 30 km/h
• Average speed (v^av) = 40 km/h

To Find:

• What should be the speed (v²) of the train to travel next 30 km?

Solution: Formula to be used here :

${v}^{av} = \frac{Total \: distanve}{Total \: time}$

or,

${v}^{av} = \frac{Total \: distance}{ {t}^{1 + }t ^{2} } \: \\ where \: t ^{1} = \frac{30}{30} = 1h \\ or \: 40 = \frac{60}{1 + \frac{30}{v ^{2} } } \\ or \: 40(v ^{2} + 30) = 60 {v}^{2} \\ so \: v ^{2} = 60 \: km/h$