Multiple choice

A man rows upstream $13$ km and downstream $28$ km taking $5$ hr each time. What is the velocity in (km/hr) of the current ?

  1. $1.0$
  2. $1.2$
  3. $1.5$
  4. $1.8$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Upstream speed = 13/5 = 2.6 km/hr. Downstream speed = 28/5 = 5.6 km/hr. Current velocity = (Downstream - Upstream) / 2 = (5.6 - 2.6) / 2 = 1.5 km/hr.

AI explanation

The speed of the boat downstream is calculated by dividing the distance by the time, which is 28 km divided by 5 hr, equaling 5.6 km/hr. The speed of the boat upstream is 13 km divided by 5 hr, equaling 2.6 km/hr. Using the boat and stream formula, the speed of the current is half the difference between the downstream and upstream speeds, so the velocity is (5.6 - 2.6) divided by 2, resulting in 1.5 km/hr.

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