a car covers 140 km distance with speed of 6 km/hr and the remaining distance with speed of 10km/hr. if it's reverses it's speed , it covers 8 km more in the same time. find the time taken by the car to cover 140 km and average speed of car.
Answers
Answer:
630 km.
Step-by-step explanation:
Time taken by car
= 52866 = 8 hours
Time = 15 hours
Speed of truck = 66 - 24 = 42 kmph
∴ Distance covered by truck
= Speed × Time
= 15 × 42 = 630 km
Answer :-
Average speed of car = 7.35 km/hr
Time taken by the car to cover 140 kilometres by average speed = 19. 04 hrs
GIVEN :-
Car covers 140 km at speed of 6 km/hr
It cover remaining distance at the speed of 10 km/hr
On reversing speed
Car covers 140 kilometre at speed of 10 kilometre per hour .
It covers remaining distance at speed of 6 kilometre per hour
It also covers 8 km extra distance in the same time which it took to cover the distance before reversing speed .
Time taken to cover both distances is same .
Solution :-
Let's assume that the total time taken by the car to cover these two distances is T hours , and remaining distance covered by car as x km .
So total distance covered 1st time is 140 + x km
Total distance covered 2nd time is 140 + x + 8 km
Time taken to cover 1st distance .
Time taken to cover 140 km by 6 km/hr speed →
Time = 23.34 hours .
Time taken to cover X kilometre by 10 km/hr speed
Time = x/10 hours ...eq 1
Total time = 23.34 + X/10 hr.
Total time taken to cover 1st distance is 23.34 + X km/hr .
Time taken to cover second distance .
Time taken to cover 140 kilometre at the speed of 10 kilometre per hour .
Time = 14 hours
Time taken to cover X kilometre at the speed of 6 kilometre per hour .
Time = X/6 hours . ..eq 2
Time Taken to cover 8 kilometre at the speed of 60 km per hour .
Time = 1.34 hours
Total time taken = 14 + 1.34 + X/6 hours
Total time taken to cover the second distance is 15.34 + X/6 hours
As it's given in the question that time taken for covering both distance is equivalent to each other .
→ Time taken to cover 1st distance = Time taken to cover 2nd distance.
→ 23 . 34 + X/10 = 15.34 + X/6
→ 23.34 - 15.34 = X/6 - X/10
→ 8 = (10x - 6x) / 60
→ 8 × 60 = 4x
→ 480/4 = x
→ X = 120 km
So the remaining distance given in the question is 120 kilometre.
Putting the value of x in equation 1
→ 120/ 10 = 12 hours
Total time taken to cover first distance = 23.34 + 12
→ Total time = 35 .34 hours ...eq 3rd
Putting the value of x in equation 2nd
→ 120/ 6 = 20 hours
Total time taken to cover second distance = 14 + 1.34 + 20
→ Total time = 35.34 hours ...eq 4th
So from equation third and fourth we conclude that time taken to cover both distances is equal to 35.34 hours
Total distance = 140 + 120 = 260 km
→ Average speed = Total distance/ total time taken
→ 260/ 35.34
→ Average speed = 7.35 km approx .
Now time taken to cover 140 kilometres at average speed →
→ 140/ 7.35 = 19 .04 hours .