Multiple choice

A boat goes 40 km down stream in one hour and the same distance upstream in two hours. The speed of the boat in still water is - एक नाव धारा के विपरीत 40 किमी की दूरी एक घण्टे में तथा उतनी ही दूरी धारा की दिशा में दो घंटे में तय करती है। शांत जल में नाव की चाल क्या है।

  1. 30 kmph / किमी./घण्टा

  2. 25 kmph / किमी./घण्टा

  3. 20 kmph / किमी./घण्टा

  4. 15 kmph / किमी./घण्टा
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Downstream speed (boat + current) = 40 km/h since 40 km is covered in 1 hour. Upstream speed (boat - current) = 20 km/h since 40 km takes 2 hours. Adding these equations: 2 × boat speed = 60, so boat speed = 30 km/h.

Keep practicing — related questions