Question

A man travels $600$ km by train at $800$ km / hr, $800$ km by ship at $40$ km/hr, $500$ km by aeroplane at $400$ km/hr and $100$ km by car at $50$ km/hr. What is the average speed for the entire distance ?

• A. $60$ km/hr
• B. $60\frac{5}{123}$ km/hr
• C. $62$ km/hr
• D. $83\frac{1}{3}$ km/hr

Answer 1

The correct option is D $83\frac{1}{3}$ km/hr

Total distance traveled $=600+800+500+100=2000$ km

Total time taken =$\frac{600}{800}+\frac{800}{40}+\frac{500}{400}+\frac{100}{50}\Rightarrow \frac{6}{8}+20+\frac{5}{4}+2\Rightarrow 24hr$

Average speed =$\frac{2000}{24}$=$83\frac{1}{3}$ km \hr