Aptitude - Time and Distance - Discussion

@Sundar,

Can you explain in an easy way?

Given in the question to find out the number of minutes the bus stops per every hour.

So let us consider that the bus travels for 1 hr. The distance travelled without stopping = 1 * 54 = 54 kms.

Let the bus stops for x mins in 1 hr. So the 54 kms are covered in 1 + (x/60) hrs (converting x mins to hrs).

So, 54 = 45 * (1 + (x/60) ) => x = 12. Now the total time taken = 1 hr + 12 min = 72 min.

This means that the bus stops for 12 min in every 72 mins. We have to calculate the time the bus stops in 60 mins.

So, (12 * 60) / 72 = 10 mins.

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?

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.