• On a 60 km straight road, a bus travels the first 30 km with uniform speed of 30 kmh -1. How fast must the bus travel the next 30 km so as to have average speed of 40 kmh-1 for the entire trip ?
Answers
Answered by
207
Given:
Total distance =60km
Average speed of entire journey=40km/h
Total Time taken =
total distance/average speed
=60/40
=3/2hr
Case :1
Let us CALCULATE time taken to cover first 30km
Speed=30km/h
Distance=30km
T=distance/ speed=30/30
=1hr -----equation ( 1)
Case: 2
Let us CALCULATE time taken to travel next 30km
Let speed be =Xkm/ h
X=30KM/t
t=30/X hours ----equation( 2)
Total time = add equation 1 and 2
=1 +30/X
Since total time =3/2 he
3/2 =1 +30/X
3/2-1 =30/X
1/2 =30/X
X=60km/h
Therefore bus should travel next 30km distance at a speed of 60 km/h
Total distance =60km
Average speed of entire journey=40km/h
Total Time taken =
total distance/average speed
=60/40
=3/2hr
Case :1
Let us CALCULATE time taken to cover first 30km
Speed=30km/h
Distance=30km
T=distance/ speed=30/30
=1hr -----equation ( 1)
Case: 2
Let us CALCULATE time taken to travel next 30km
Let speed be =Xkm/ h
X=30KM/t
t=30/X hours ----equation( 2)
Total time = add equation 1 and 2
=1 +30/X
Since total time =3/2 he
3/2 =1 +30/X
3/2-1 =30/X
1/2 =30/X
X=60km/h
Therefore bus should travel next 30km distance at a speed of 60 km/h
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Answered by
0
Answer:
Average Velocity = s1+s2t1+t2=2×v1v2v1+v2s1+s2t1+t2=2×v1v2v1+v2 40 km/hr = 2×30kmhr×v230kmhr+v22×30kmhr×v230kmhr+v2 2 = 3v230kmhr+v23v230kmhr+v2 60 km/hr +2v2 = 3v2 v2 = 60 km/hr 60-km-straight-road-a-bus-travels-the-first-30-km-with-a-uniform-speed-of-30-kmh-1
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