Mahindra Comviva Time, Speed & Distance Problems with Solutions Quiz -1

Although this question can be solved by making a simple equation, still the use of ratio can eliminate the calculation-work.
Since, the current speed is 3/4th the average speed, we can take the current speed as 3km/hr and the average speed as 4km/hr so that the ratio of the speeds is 3:4.
As the distance covered is same in both the cases, so the time taken will be in the ratio 4:3 (in the reverse ratio of speeds).
It means that if today, I took 4 minutes then on an average I take 3 minutes i.e. I am one minute late.
Now apply simple chain rule that, if I am late for 1 minute, the usual time taken is 3 minutes and if I am 25 minutes late, the normal time taken will be 25 x 3 = 75 minutes.

In this question the thief travelled for the first 30 minutes. The speed of thief is 60 km/hr, so he has covered 30 km in 30 minutes.
The ratio of speeds of thief and police is 60: 80 or 3: 4.
Excluding the first 30 minutes, the thief and the police have run for the same time. So the distance covered is in the ratio of their speeds i.e. 3: 4.
Since, the initial distance between the thief and the police if 30 km, so in total, thief and police have covered 90 km and 120 km respectively (to make the ratio 3:4).

In this question, Amit and Bimal are moving towards each other. So their relative speed is 20 + 24 = 44 km/hr. The speed of the bird is 176 km/hr.
Now, the logic is simple. The bird flies for the same time as both Amit and Bimal take to meet.
Since the time taken by Amit and Bimal together and the bird is same, so the distance covered will be in the ratio of their speeds.
The ratio of the speeds is 44: 176 or 1: 4. Hence, if Amit and Bimal cover 800 m, the bird will cover 800*4 = 3200 m.

⇒ Raman's speed = 20 km/hr = 20 × 5/18 = 50/9 m/sec
⇒ 400 × 9/50 = 1⅕ mins

Average speed of John = 2xy/x+y = 2 × 25 × 4 / 25 + 4= 200/29 km/h
⇒ Distance traveled = Speed × Time = 200/29 × 29/5 = 40 Km
⇒ Distance between city and town = 40/2 = 20 km

⇒ Lenght of train = 20 × 10 = 200 meters

⇒ If Ram is walking at ⅚ of his usual speed that means he is taking 6/5 of using time.
⇒ 6/5 of usual time - usual time = 10 mins
⇒ 1/5 of usual time = 10 mins
⇒ Usual time = 50 mins

⇒Reduced speed = 65-15 = 50 km/h
⇒ Now car will take 65/50 × 60 mins = 78 mins

⇒Time taken by A to cover 100 meters = 60 seconds
⇒ Since A gives a start of 4 seconds then time takes by B = 72 seconds
⇒ B takes 72 seconds to cover 96 meters
⇒ Speed of B = 96/72 = 1.33 m/s

⇒ While A covers 1000 meters, B can cover 900 meters
⇒ While B covers 1000 meters, C can cover 900 meters
⇒ Lets assume that all three of them are running same race. So when B runs 900 meters, C can run 900 × 9/10 =810
⇒ So A can beat C by 190 meters.