Aptitude - Time and Distance - Discussion

Bus A travels 54km in 60 min that means to travel 1km it takes(60/54) 1.11min.
Bus B travels 45km in 60min with stoppages.

Here, the speed of both the buses are same but bus B gives stoppages that's it.
i.e. both A & B bus covers 1 km in 1.11min only. So if bus B takes 1.11min to travel 1km then to cover 45km it will take 45 * 1.11 = 50min(actually travelled time without stoppages ).

So, the time T = travelled time with stoppages - travelled time without stoppages.
T = 60 - 50 = 10 mins.

Here distance is constant.

Let x be the time for which the vehicle speed.
Hence, 54 * (60 - x) = 45 * (60).......(s1 * t1= s2 * t2).
x = 10 min is the answer.

Can anyone explain it clearly, please?

@Ravi.

We have been given speeds with stoppages and without stoppages,i.e., 45KM/h(with stoppages) and 54 Km/h( without stoppages).

Now, the question wants us to find that how much time is consumed in those stoppages.

Here the value of speed is based upon the time it took to reach a particular distance.

So naturally with stoppages the time will be more so for same distance the average speed is reduced i.e., 45Km/h.

Without stoppages, speed will be 54km/h.

Now consider the time to be one hour.Why one hour, because question wants us to find the minutes the bus stop per hour. Per hour.

So what is the distance for One hour at 54km/h and 45km/h?

Distance = 54KM and 45KM.
Now, what is the difference between these two?
9Km.
This is done to find what stoppages cost in term of distance between two buses.

Now, why 54Km?
Since you already know the difference in distance due to stoppages you need to use the speed with which the bus is covering that stoppage distance.

So,
9/54 = 1/6hr.
To convert this into minute just multiply it with 60 and you will have a number of minutes.,i.e., 10 Mins.

Is it clear now Ravi?

The speed of a train is 80 kmph and for every bogie added, the speed decreases by 10%. How many minimum numbers of bogies should be added to reduce the speed of the train to less than 50 km/h?

Can anyone tell me the answer?

Explanation:

Excluding stoppages (ES) - 54.
Including stoppages (IS) - 45.
Formula: (ES - IS)/ ES.
=> (54 - 45)/54 = 9/54 = 1/6 hrs (or) 10 mins.

Nice explained @Jaya and @Kaushal.

Car travels with an average speed of 70 km/hr from Magallanes interchange to bicutan in 5 mi how far are these two places? How fast is the car travelling after 2 mi?

Please sole this.

This can be done using allegations easily.

54 0
45
45 : 9

That is 5:1.

So, it should not travel for 1/6 of an hour that is 10 min.

Thank you for all your simple explanations.