Question

A car travels first 30 km with a uniform speed of
60 km h and then next 30 km with a uniform speed
of 40 km h- Calculate : (i) the total time of journey,
(11) the average speed of the car.​

Answer 1

Answer:

total time taken = 5/4 hrs = 1hr 15 min

Explanation:

first 30 km 60km/h

time taken = dist/speed =30/60

=1/2 an hour

next dist = 30km

speed = 40km/h

time taken = 30/40 = 3/4 hour

(i) total time taken = 1/2 + 3/4= 5/4 hrs

(ii) avg speed = total dist / total time

= 60/(5/4) =(60×4)/5

=48 km / hr

Answer 2

Answer:

Explanation:

total distance=30 km +30km

total distance=60km

total distance=60000m

first speed=60km/h

first speed=60000/3600

first speed=16.6m/s

second speed=40km/h

second speed=40000/3600

second speed=11.1m/s

average speed=(first speed +second speed )/2

average speed=(16.6+11.1)/2

average speed=(27.7)/2

average speed=13.85m/s

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