Aptitude - Time and Distance - Discussion

Here time is never given.

So consider man named.

Ashok walk with speed 10 km/hr, he travel for next 2 hour so distance he cover is 20 km.

2nd person named.

Madhu walk with speed 14 km/hr, he also travel for 2 hour so distance he cover is 28 km.

Now Madhu travel more 20 km wit speed 14 km/hr. So we subtract that 20 km from distance he travel in 2 hour.

= 28-20 = 8 km.

It means if we consider time 2 hour. Which is not given, so the answer will be 8 km?

Is it true?

It came by this formula S = D/T (Speed = Distance/Time).

Here we take this formula such as:

T = D/S.

Let consider actual distance x km.

T = x/10.....(1).
T = x+20/14.....(2).

Taking both the times together we get from (1) and (2).

x/10 = x+20/14.
14x = 10x+200.

4x = 200.
x = 50km.

Hope you get it now.

I can't understand please explain clearly.

Actual distance traveled be X km.

X/10 = X+20/14.

X = 50 kmph.

Let time taken to go certain distance = t hours.

At speed of 10kmph, distance covered = 10t kms.

At speed of 14kmph, distance covered = 14t kms.

Because, 10t < 14t.

Therefore, 10t + 20 kms = 14t.

=> 14t - 10t = 20 kms.
=> 4t = 20 kms.
=> t = 5 hours.

Now, his actual speed is 10kmph.

Therefore, actual distance covered = 10t = 50kms.

Guys if two boys are given a constant time (10min). One boy who walks little slower covered small distance 500m only at 10min. Another boy who walks faster covers more distance 800m at that constant time (10min). If time is kept constant means only distance covered varies.

Likewise If a constant distance given means time taken by two boys to reach that distance varies.

Can you provide proper steps of answer? I'm not getting it.

See if the person generally walk at the speed of 10 km/hr but he walk 14 km/hr and by this speed he walk 20 km more. Means from this extra 4 km speed he covers the extra distance of extra 20 km in 5 hours.

So if he walk 5 hour at the speed of 10 km/hr the distance cover is 50 km and with the speed of 14 km/hr he covers 70 km. But he is a man and he has its stamina also means more speed less time of walking because he tired at the same point of his body capacity in both speed.

So if he will a machine then the answer is 70 km but he is a man and hence we have to deduce the extra 20 km and the answer is 50 km.

First calculate as:

Time = Distance/Speed = 20 km/14-10 kmph = 20/4 = 5 hr.

Means time = 5 hr.

Distance = Time*Actual speed.

Distance = 5*10 = 50 km.

I think answer here should be 70 km as, here actual distance travelled is asked for which speed is 14 km/hr.

Let actual distance travelled is x, then.

x/14 = x-20/10.

Gives x = 70.