[shalini]

Bhars?

we sure would like to know the answer.....i didnt really understand the question properly!!!!!

[bhars18]

Bhars?

we sure would like to know the answer.....i didnt really understand the question properly!!!!!

I thought you'd see Raghu's solution as well

5/2 is the answer as he gets it.

Bharathi.

[rani_das]

Average speed of a vehicle is 60kmph when stoppages r nt considered . When stoppages r considered the average speeed becomes 48 kmph . On an average how many minutes per hour are the stoppages ?????????? plz give me a detailed explanation chao for now

[catdog]

Originally Posted by rani_das

Average speed of a vehicle is 60kmph when stoppages r nt considered . When stoppages r considered the average speeed becomes 48 kmph . On an average how many minutes per hour are the stoppages ?????????? plz give me a detailed explanation chao for now

Assuming distance to be 60 KM .....it takes 1 hr without stoppage ....if he takes stoppage he takes
60/48 hrs i.e (60/4*60 minutes .......75 minutes ................this implies he stopped for 15 minutes ...............


75 minutes 15 minutes stops

so in 60 minutes

60/75*15

12 minutes /hr ..........

[thakarsagar]

Originally Posted by rani_das

Average speed of a vehicle is 60kmph when stoppages r nt considered . When stoppages r considered the average speeed becomes 48 kmph . On an average how many minutes per hour are the stoppages ?????????? plz give me a detailed explanation chao for now

Another method...

x = normal time for reaching the destination.
y = total stoppage time.

60/48 = (x+y)/x
=> x = 4y.

Average time of stoppage = y/(x+y) = 1/5 .

[chammo]

[QUOTE=raghuveer_v]I am sorry Bharti, if I sounded harsh in my previous post. Thanks for the clarifications.

My solution:

Actual Speed of M1 = [18 + 18x3] kmph
Actual Speed of M2 = [36 + 36x3] kmph

(Relative) Speed of approach of the men towards each other = sum of the above two = 216 kmph = 216000 mph

Distance to be covered = 150m

Time (in hours) = distance/speed = 150m / 216000 mph

Time (in seconds) = 150*3600/216000 = 2.5 sec


See how u got the speed of train as 72 kmph and 144 kmph. The actual speed of M1 shd be 2.5 mps and actual speed of M2 shd be 5mps, so that speed of T1 is 7.5mps and speed of T2 is 15mps. This will suffice the given condition that relative speed of M1 wrt T1 is 5mps(18kmph) and relative speed of M2 wrt T2 is 10mps(36kmph).
Anyways these all calculations are not necessary as we are straightaway given the relative speeds of T1 n T2.
So we can assume that both the trains are stationary n only the two men r moving towards each other.

Now
total distance to be covered by both of them before they meet is 150 m and the rel spped of M1 wrt M2 is 15mps.

so time taken =150/15=10 s which shd be he right answer.

What say guys

[rani_das]

Ravi n Vikram complete one round of 900 in 9s n 15s respectively

thn their speeds r 100m/s n 60m/s wth rlative speed of 40 m/s


thn guys can u plz explain me how cme ravi overtakes vikram in every 20 seconds????:whatthat:

how ths overtaking time is calculated?????????????:whatthat:

[pendyal]

Originally Posted by rani_das

Ravi n Vikram complete one round of 900 in 9s n 15s respectively

thn their speeds r 100m/s n 60m/s wth rlative speed of 40 m/s


thn guys can u plz explain me how cme ravi overtakes vikram in every 20 seconds????:whatthat:

how ths overtaking time is calculated?????????????:whatthat:

its not 20 s but 22.5 seconds.

ravi and vikram start off at the same time.....

lets assume that ravi first overtakes vikram after 't' seconds.

now in this 't' seconds ravi would have covered 100t metres.....and vikram 60t metres.......but since ravi is overtaking vikram he should have covered one round more than vikram i.e. 900 metres.

so 100t - 60t = 900
or 40t = 900 and t = 22.5 seconds

now similarly for the next time ravi overtakes vikram we can assume safely that they are starting off afresh from the point where ravi first overtook vikram....

hope this answers ur question

[ganeshiyer]

Originally Posted by rani_das

Ravi n Vikram complete one round of 900 in 9s n 15s respectively

thn their speeds r 100m/s n 60m/s wth rlative speed of 40 m/s


thn guys can u plz explain me how cme ravi overtakes vikram in every 20 seconds????:whatthat:

how ths overtaking time is calculated?????????????:whatthat:

i guess for these type of problems u can directly use the following formula

time taken to overtake= [total distance]/[relative speed]
i.e t=900/40 =22.5

[Vedvyas]

Originally Posted by catdog

Assuming distance to be 60 KM .....it takes 1 hr without stoppage ....if he takes stoppage he takes
60/48 hrs i.e (60/4*60 minutes .......75 minutes ................this implies he stopped for 15 minutes ...............


75 minutes 15 minutes stops

so in 60 minutes

60/75*15

12 minutes /hr ..........

Yet another Simple method:

Assume that the distance is 60 * 48 km (No need to calculate the value)

When average speed = 60 kmph => time = 48 hrs. (Without stoppages)
When average speed = 48 kmph => time = 60 hrs. (With stoppages)

Hence stoppage time for same distance = 60 - 48 = 12 hrs.

Total time with stoppage = 60 hrs.

Hence average stoppage time = 12/60 hrs = 1/5 hrs = 12 mins.

No calculations needed at all.

Cheers,

Ved