73rd &74th

73.
Two trains each 1/6 mile in length run in opposite dirctions to each

other with equal speed of 60 miles/hour. What is the time taken to completely

cross over the two trains.

74.A man wearing a hat stands on a bridge across a river. At an instant his hat falls

into the river and starts flowing along with the atream at the same speed of the stream.

At the same instant the man jumps into the river and starts swimming in the direction

opposite to the stream, like that he swims for 10 minute , then he turns back and

starts swimming in the direction of the stream to retrieve the hat. He retrieves the hat

under another bridge which is 1000 yards away down the stream from the first bridge.

What is the speed of the river.