Aptitude - Time and Distance - Discussion

If he is going at 10km/hr the distance is 10*t.
If he is going at 14km/hr the distance is 14*t.
The difference = 20km
14t-10t = 20
4t = 20
t = 5 hours
Now, actual distance = 10 * 5.
= 50 km.

@All,

According to me, the solution is;

For every 1 km/hr there is 5 km distance travelled;
So for 10km/hr there is 50km distance travelled;
which means for 4 more km/hr in question there is 20 kM distance.
So, for 10 km it's 50 km.

Let the actual speed be x.
Let the time be y.

Distance = Speed * time

Therefore,
X= 10y.

But, now he would have travelled 20 km more if the speed was 14km/hr.
therefore,
14x= y+20.

Subtracting both equations,
14x = y+20,
10x = y.

we get;
4x = 20,
x = 5.
Put y in the equation
10 * 5 = 50 Kms.
Verify it by putting 5 in both equations.

Good to understand. Thanks everyone for explaining the answer.

Let,
Actual dist = X(at-10km\hr).
x/10 = x + 20/14,
14x = 10x + 20,
14x - 10x = 20,
4x = 20,
x = 20/4,
x = 5.

The actual distance at 10kmph * actual distance.
= 10 * 5,
= 50km.
So, the answer is 50km.

Let distance travelled by person at 14km/h be d1 and distance travelled at 10km/h be d2.

d1-d2=20km (given in Q that he walks 20km more)
D=speed * time.

{Time is constant and reason is;

It is because supposed for example if a person walks 10km/h for 7 hrs means he would have covered 70km. If speed changes to 14km/h and if we assume time is not constant then to cover 70km distance at 14km/h 5hrs would be needed, then in such case there would be no case of extra distance covered like in present Q which is 20km.

If time is constant like 7hrs so at distance at 10km/h =70km & 14km/h=98km and only then we can say it travelled 28km extra)}

Now coming to the present Q,
d1-d2=20km,
14t-10t=20.
t(14-10)=20.
4t=20.
T=5hr.

Q says if a person walks 14km/h that means 14km/h is not the original speed...
D=10*5=50km.

According to me, the right answer is 50km.

For the same interval if the person travelled in 14 kmph so only.

or else you could solve like this

1st hour 10 =14
2nd hour 20 =28
3rd hour 30 =42
4th hour 40 =56
5th hour 50 =70

At speed 10 kmph he reaches 50 km at the same time if he travels in 14 kmph he would reach 70 km. So 70 - 50 = 20. I think u got it.

I'm not clear with the answer. Why did you take the time same in both the cases?

Explain it clearly.