Unitary Method ...

Renu can row her boat at the speed of 4 km/hrin still water. If it takes one hour more to row the boat 4.8 km upstreamthan to return downstream. Find the speed of the stream.

Two person’s P and Q start at the same time fromcity A for city B, 80 km away. P travels 6 km/h slower than Q. Q reaches city Band at once turns back meeting P, 14 km from city B. What is speed of P?

Two stations A and B are 170 km apart on astraight line. One train starts from A at 6 a.m. and travels towards B at 30km/h. Another train starts from B at 7 a.m. and travels towards A at a speed of40 km/h. At what time will they meet?

Out of a total distance covered of 300 km,first half is covered at the speed of 50 km / hr and the remaininghalf is covered at 25 km/hr. Find the total time taken to cover thewhole journey. 

Two trains start at the same time from A andB and proceed toward each other at the speed of 60 km hr and 40 km/hrrespectively. When both meet at a point in between, one train was found to havetravelled 125 km more than the other. Find the distance between A andB. 

A train travels 102.5 km/hr. How many meterswill it travel in 20 minutes? 

The speed of a boat in still water in 20 km/hrand the rate of current is 5 km/hr. The distance travelled downstream in 15minutes is:

What is the distance travelled at the speed of50 km/hr for $\frac{1}{5}$hours?

Man makes a trip by automobile at an average speed of 80 km/hr. He returns over the same route at an average speed of 40 km/hr. His average speed for the entire trip is: 

Simran drove 60 miles to see hercousin and at 40 mph. The trip took Simran 1 hour. Then,Simran drove from her cousin’s house and drove another 50 milesto the store at a speed of 20 mph. It took Simran 4 hoursto arrive at the store. What was Simran’s average speed for the trip?

A train 300 m long is running at a speed of 54km/hr. In what time will it pass a bridge 150 m long?

A car travelling at a speed of 60 km/ hour cancomplete a journey in 10 hours. How long will it take to travel the samedistance at 80 km/hour? 

A man covers a certain distance between hishouse and office on a scooter. Having an average speed of $20 km/hr$, he reachesoffice late by $15 minutes$. However, with a speed of $50 km/hr$, he reaches hisoffice $10 minutes$ earlier. The distance between his house and office is-

It takes 10 seconds for a train travelling at 50km/hr to cross entirely another train half its length and travelling inopposite direction at 42 km/hr. It also passes a bridge in 41 seconds. Thelength of the bridge is:

When a person leaves his home for picnic by hiscar, the meter reads 14250 km. When he returns home after two hoursthe reading is 14315 km, during journey he stays for 20 minutes atmidway. What is the average speed of the car during this period?