Boojho walks to his school which is at a distance of 3 km from his home in 30 min. On reaching, he finds that the school is closed and comes back by a bicycle with his friend and reaches home in 20 min. His average speed in km/h is [NCERT Exemplar]
(a) 8.3
(b) 7.2
(c) 5
(d) 3.6
Answers
Boojho walks to his school which is at a distance of 3 km from his home in 30 min and comes back by a bicycle (for 3 kms) with his friend and reaches home in 20 min
Hence the total distance covered =3 + 3 =6km
Total time taken = 30+20=50min
=50/60hr=0.83 hr
Average speed
=total distance/total time
=6/0.83
=7.2
I hope this helps ( ╹▽╹ )
Boojho walks to his school which is at a distance of 3 km from his home in 30 min. On reaching, he finds that the school is closed and comes back by a bicycle with his friend and reaches home in 20 min. His average speed in km/h.
Solution
From home to school distance is given as 3 km time taken is 30 min = (30/60) hour = 0.5 hour
And in returning from school to home time taken = 20 min = (20/60) hour = 0.33 hour
average speed = Total distance / time taken
= (3 + 3)/(0.5 + 0.33) km/h
= 7.2 km/h