Given: Inner diameter =14cm Water flows rate =154 litres per minute Concept used: Volume of a cylinder =πr2h Here, r= radius h= height or length Calculation: The Volume of water that flows in one hour =(154×60) liters. [ ∵1 hour =60mins ] Volume in cm3=(154×60×1000)cm3[∵1 litre =1000cm3] Inner radius of the pipe =14∕2=7cm. Let the length of column of water that flows in 1 hour be Hcm. According to the question, πr2H=(154×60×1000) ⇒(22∕7)×72×H=(154×60×1000) ⇒22×7×H=(154×60×1000) ⇒154H=(154×60×1000) ⇒H=60000cm or 0.6km ∴ The speed of water in km∕hr is 0.6