Question

a car moves a distance of 200 metre it covers first half of the distance at a speed 60 kilometre per hour and the second half at speed v.if the average speed is 40 kilometre/h. the value of V is ​

Answer 1

Answer:

v=30 km/hr

Explanation:

given: <v>=40 km/hr.,s=200 m.,

s1=100 m.,v1=60 km/hr.,t=?(5/3 hr)..since wkt.,speed=distance/time

s2=100 m.,v2=v km/hr.,t=100/v..,since wkt.,speed=distance/time.,

we hv..,

<avg. speed>=total distance/total time

<v>=200/(t1+t2).,

40 km/hr=200*3v/(5v+300)

=>200v+12000=600v

=>400v=12000

i.e v=30 km/hr..!