Quiz Discussion

A boat while dowenstream in a reiver converd a distance of 50 miles at an average speed of 60 miles per hour. While returning , because of the water resistance , it took 1 hour 15 minutes to cover the same distance What was the average speed during the whole journey?

• 1] 40 mph
• 2] 48 mph
• 3] 50 mph
• 4] 55 mph

A man can row 6 km/hr in still water. If the speed of the current is 2 km/hr he takes 4 hours more in upstream than the downstream. The distance is?

• 1] 30 km
• 2] 24 km
• 3] 20 km
• 4] 32 km

A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:

• 1]

  4

• 2]

  5

• 3]

  6

• 4]

  10

A boat covers a certain distance downstream in 1 hour, while it comes back in \(1\frac{1}{2}\) hours. If the speed of the stream be 3 kmph, what is the speed of the boat in still water?

• 1] 12 kmph
• 2] 13 kmph
• 3] 14 kmph
• 4] 15 kmph
• 5] None of these

A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is:

• 1] 2 : 1
• 2] 3 : 1
• 3] 3 : 2
• 4] 4 : 3

A man rows 12 km in 5 hours against the stream and the speed of current being 4 kmph. What time will be taken by him to row 15 km with the stream?

• 1]

  1 hour \({ \text{27}}\frac{7}{{13}}\) minutes

• 2]

  1 hour \({ \text{24}}\frac{7}{{13}}\) minutes

• 3]

  1 hour \({ \text{25}}\frac{7}{{13}}\) minutes

• 4]

  1 hour \({ \text{26}}\frac{7}{{13}}\) minutes

A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, find the time taken by the boat to go 68 km downstream.

• 1]

  2 hours

• 2]

  3 hours

• 3]

  4 hours 

• 4]

  5 hours

A man can row three-quarters of a kilometer against the stream in \(11\frac{1}{4}\) minutes and down the stream in \(7\frac{1}{2}\) minutes. The speed (in km/hr) of the man in still water is:

• 1] 2
• 2] 3
• 3] 4
• 4] 5

There is a road beside a river. Two friends started from a place A moved to a temple situated at another place B and then returned to A again. One of them moves on a cycle at a speed of 12 km/hr, while the other sails at a speed of 10km/hr. If the river flows at a speed of 4km/hr, which of the two friends will return to place A first.

• 1]

  7.4 km/h

• 2]

  8.4 km/h

• 3]

  2.3 km/h

• 4]

  8.6 km/h

A man can row at a speed of \(4\frac{1}{2}\) km/hr in still water. If he takes 2 times as long to row a distance upstream as to row the same distance downstream, then the speed of stream (in km/hr) is-

• 1] 1
• 2] 1.5
• 3] 2
• 4] 2.5