Aptitude - Time and Distance - Discussion

If it is asked about Sameer's speed then what would be the answer?

Let time taken by Sameer be "t".

First case: when the time taken by Sameer is "t", time taken by Abhay is "t + 2".

Let the speed of Abhay be "s".

Second case: when the speed of Abhay is "2s" time taken by him is "t - 1".

Now from case one and case two, it can be said as,

S = 30/(x + 2) -----> equation (1).

2s = 30/(x - 1) -----> equation (2).

Now substitute "s" value in equation (2).

Thus we get the value of t = 4 hours.

Now Speed of Abhay = 30/(x + 2) = 30/(4 + 2) = 30/6 = 5 hours.

Abhay takes 2 hours and if doubles her speed he takes 1 hour less than Sameer so,

2 - (-1) = 3.

If the distance is same then,

Sameer's speed = 30/4.
= 7.5 km/hr.

Thanks, @Devi. Very nice explanation.

Thanks @Devi.

Thanks @Devi.

Total = 30 km.
Speed = 1 : 2.
That is time = 2 : 1.
Difference between time is 1 = 3(3 get from question is more than 2 hrs and less than 1 hrs)
2 * 3 = 6;
Abhay speed =30/6 = 5 km/hrs.
Sameer speed = 30/4 = 7.5 km/hrs.

Let total time Sameer = x hours.
Total time Abhay = x + 2 hours.
Speed Sameer = 30/x kmh.
Speed Abhay = 30/(x + 2) kmh.
If speed a two times = 2(30/x + 2) kmh.

So, 2(30/x + 2) km = 1 hour.
1. km=1/2(30 x+2),
30. km=30/2(30/x+2).

According to question,
x - 30/ 2(30/x + 2) = 1,
x = 4 h.

Speed Abhay = 30/x + 2 kmh,
= 30/4 + 2 = 5 kmh.

Only consider Abhay the ratio of his speeds is 1 : 2.
So, the ratio of time he would take would be 2 : 1.
2x for 1 case and x for 2.
Given 2x - x = 3
so, x = 3hrs.

So, for 1 case he will take 6 hrs to complete the journey.
His speed will be 30/6 = 5km/hr.