Question

Swati can row a boat on still water at a speed of 5 km/hr. However, on a given river, it takes her 1 hour more to row the boat 12 km upstream than downstream. One day, Swati rows the boat on this river from X to Y, which is N km upstream from X. Then she rows back to X immediately. If she takes at least 2 hours to complete this round trip, what is the minimum possible value of N?

• A. 3.9 km
• B. 2.2 km
• C. 3.8 km
• D. 3.6 km
• E. 4.8 km

Hint:

In geometry problems with diagrams, identify the key relationships (similar triangles, right angles, parallel lines) to set up the equations.

Answer 1

Answer: (E)

Step 1: Analyze the geometry diagram.
Step 2: Apply relevant geometric theorems (Pythagoras, similarity, etc.) to find the required length.
Step 3: Calculate the value based on the given dimensions.
Step 4: Final Answer: The correct options from the given choices.