9.
A car travels at 50 km hr for the first half time
of the journey, at 25 km/hr for the half of the
remaining time of the joumey, at 12.5 kin/hr
for the half of the remaining time of the journey
and so on until the car accomplishes its
journey. The average speed of the car is
approximately equal to
(a) 100 km/hr (b) 50 km hr
(c) 33 kın hr (d) 25 km hur
1
Answers
Answer:
the correct option is B
The average speed of the car = 50 km/hr.
The car travels straight path for first half time and second half time. The average speed for the travel journey is calculated over total distance travelled and total time for the travel.
Given, speed1 = 40 km/hr and speed 2 = 60 km/hr.
Let us assume that the total time taken for the travel be x.
So, we have, distance travelled in first half be,
Time taken for first half be time1 = half of total time
.
And, distance travelled in second half be,
Time taken for second half be time2 = half of total time
Thereby, Average speed = total distance / total time
Total distance
Total time = x
Average speed .