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NTPC Graduate Tier 1 2016 Shift 2 📅 02 Apr, 2016

The upstream speed of the boat is 40 km/hr and the speed of the boat in still water is 55 km/hr. What is the downstream speed of the boat?

A
75 km/hr
B
70 km/hr
C
60 km/hr
D
65 km/hr
Result Summary
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APEDIA

NTPC Graduate Tier 1
2016 • 02 Apr, 2016 • Shift 2
The upstream speed of the boat is 40 km/hr and the speed of the boat in still water is 55 km/hr. What is the downstream speed of the boat?
Correct Answer
70 km/hr
Hydrodynamic Principles: In standard mathematical boat navigation problems, the upstream speed is strictly defined as the speed of the active boat minus the opp......
💡 Analysis & Explanation
Hydrodynamic Principles
In standard mathematical boat navigation problems, the upstream speed is strictly defined as the speed of the active boat minus the opposing speed of the river current (B - S). We are provided B = 55 km/hr and Upstream Speed = 40 km/hr.
Current Velocity Calculation
Utilizing the core formula, 40 = 55 - S. Systematically solving for S cleanly reveals the exact speed of the stream is 15 km/hr.
Downstream Calculation
Downstream speed represents the native speed of the boat naturally propelled further by the aiding current (B + S). Substituting the acquired values algebraically yields 55 + 15.
Conclusion
The mathematically exact downstream speed is accurately calculated to be 70 km/hr.