Question

A car travels first 60km of its journey with speed of 20km/hr next 90km with speed of 45km/hr.The average speed of the car is​

Answer 1

Answer:

30km/hr

Explanation:

take out the the time by speed and distance.t=d/s . (in both cases)

then easily take out average speed by dividing total distance by total time...

Answer 2

Answer:

first car travel d=60km, s=   20km/hr, s=  d/t then  t= s/d =20/60=0.33  then second car travel  d=90km,s=45km/hr ,s=d/t  =t=s/d =90/45 =2  now average speed is =total distance travel by total time taken ,   means, 60+90/0.33+2 =150/ 2.33= 64.37768...km/hr