In a kilometer race, A can give B a start of 100 m or 15 seconds. How long does A take to complete the race?

A takes twice as much time as B and thrice as much as c to complete a piece of work. They together complete the work in 1 day. in what time, will A alone complete the work. 

Speed of boat in still water is 9 km/hr. Stream speed initially is 2 km/hr but it increases by 3 km/hr after every hour. Find the time after which boat will come back to the position where it started.(in hour)

Vishnu travelled equal distances at speeds of 10 km/hr, 30 km/hr and 8 km/hr and took a total of 15.5 minute to complete. Find the total distance he travelled in km.

If the speed of the boat in still water is 20 km / h and the speed of the stream is 5 km / h, then how long will it take for the ferry to travel 100 km with the speed of the stream?

Tom follows Jerry. In the same time Tom jumps 8 times and Jerry jumps 6 times. But the distance that Tom travels after jumping 7 times is equal to the distance that Jerry goes after jumping 5 times. What is the ratio of the speed of Tom and Jerry?

Some students went on a field trip. At a speed of 6 km/h, they travelled by bikes for 2 hours; then at a speed of 2 km/h, they walked for another hour; then they took rest for an hour and had lunch for half an hour; then at a speed of 1 m/s, they walked for an hour to visit a garden; and finally at a speed 4 km/h, they returned home in 3 hours. Their average speed, in km/h, (rounded off to two places of decimal) is:

At an average of 80 km/hr Shatabdi Express reaches Ranchi from Kolkata in 7 hrs. Then the distance between Kolkata and Ranchi is