A boat goes 15 upstream and  downstream in 3 hours 15 m

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

11.

A man rows down a river 15 km in 3 h with the stream and returns in 7 1 half straight h. The rate at which he rows in still water is

  • 2.5 km/h

  • 1.5 km/h

  • 3.5 km/h

  • 4.5 km/h

48 Views

Advertisement

12.

A boat goes 15 upstream and 10 1 half km downstream in 3 hours 15 minutes. It goes 12 km upstream and 14  km downstream in 3 hours. What is the speed of boat in still water.

  • 4 km/hr

  • 6 km/hr

  • 10 km/h

  • 14 km/hr


C.

10 km/h

Let speed of boat with downstream = x km/hr.
      speed of boat with upstream = y km/hr.
According to the question,
  fraction numerator 21 over denominator 2 straight x end fraction space plus space 15 over straight y space equals space 3 1 fourth space equals space 13 over 4 space space space space space space space space space space space space space... left parenthesis straight i right parenthesis
14 over straight x space plus space 12 over straight y space equals space 3 space space space space space space space space space space space space space space space space space space space space space space space space space... left parenthesis ii right parenthesis
Solving (i) and (ii), we get
  x = 14,  y = 6
∴  Speed of boat in still water

equals space 1 half left parenthesis straight x space plus space straight y right parenthesis space equals space 1 half left parenthesis 14 space plus space 6 right parenthesis space equals space 20 over 2 space equals space 10 space km divided by hr.
                 




Advertisement
Advertisement