A man rows a boat 30 km downstream in 3 hours and returns upstream in 6 hours. Find the speed of the stream. MCQ with Answer and Explanation

Explanation:
Stoppage time per hour = (60 - 50) / 60 = 10 / 60 = 1/6 hour. In minutes = (1/6) * 60 = 10 minutes.

Explanation:
Let original speed be s. 360 / (s - 10) - 360 / s = 2 => 180 / (s - 10) - 180 / s = 1 => 180(10) = s(s - 10) => 1800 = s(s - 10). Solving s^2 - 10s - 1800 = 0 gives (s - 45)(s + 40) = 0. Since speed is positive, s = 45 km/h.

Explanation:
In 1 hour, distance covered by A = 45 km, and by B = 60 km. Direct distance = sqrt(45^2 + 60^2) = sqrt(2025 + 3600) = sqrt(5625) = 75 km.