Question

A boat in the river Ganga near Rishikesh covers 24 km upstream and 36 km downstream in 6 hours while it covers 36 km upstream and 24 km downstream in $6\frac{1}{2}$ hours. Consider speed of the boat in still water be x km/hr and speed of the stream be y km/hr and answer the following questions.

Represent the 2^nd situation algebraically.

• A. $36x+24y=\frac{13}{2}$
• B. $\frac{36}{x+y}+\frac{24}{x-y}=\frac{13}{2}$
  
• C. $36x-24y=\frac{13}{2}$
  
• D. $\frac{36}{x-y}+\frac{24}{x+y}=\frac{13}{2}$
  

Answer 1

The correct option is D $\frac{36}{x-y}+\frac{24}{x+y}=\frac{13}{2}$


We know that, Time = $\frac{distance}{speed}$
Speed of boat upstream = x - y km/h
Speed of boat downstram = x + y km/h
Thus, algebraically 2^nd situation is represented as
$\frac{36}{x-y}+\frac{24}{x+y}=\frac{13}{2}$