Question

What is the time taken by a boat to travel 120km upstream and back to the starting point if the speed of the boat is 25 km/hr, and the speed of stream is 5km/hr?

• A. 8 hours
• B. 12 hours
• C. 14 hours
• D. 10 hours

Answer 1

Answer:

D. 10 hours

$$Speed of Boat = 25 km/hr</p><p style="color: rgb(0,0,0); margin-top: 2px; margin-bottom: 2px" data-pxy="true">$$ Speed of Stream = 5 km/hr

$$Distance = 120 km</p><p style="color: rgb(0,0,0); margin-top: 2px; margin-bottom: 2px" data-pxy="true">$$Time Taken to Cover 120km Distance upstream and Downstream is,

$=\frac{120}{(25-5)}+\frac{120}{(25+5)}$

$=\frac{120}{20}+\frac{120}{30}$

$=6+4$

$=10hours$