Question

A man travels in a car from his village to a town at a speed of 40 kms/hr for 5 hours. There he spends an hour moving about 10 kms. He then returns to his village at a speed of 50 kms/hr. His average speed over the whole journey ( in kms/hr ) is:
A) 25
B) 40
C) 41
D) 50

Answer 1

Dear Student,

$$\begin{gathered} \mathrm{According}\mathrm{to}\mathrm{the}\mathrm{given}\mathrm{question},\mathrm{man}\mathrm{travels}\mathrm{at}\mathrm{the}\mathrm{speed}\mathrm{of}40\mathrm{km}/\mathrm{hr} \\ \mathrm{for}5\mathrm{hours}. \\ \mathrm{Therefore},\mathrm{the}\mathrm{distance}\mathrm{travelled}\mathrm{by}\mathrm{the}\mathrm{man}\mathrm{in}5\mathrm{hours}=40\times 5=200\mathrm{km} \\ \mathrm{Also},\mathrm{he}\mathrm{spends}1\mathrm{hour}\mathrm{and}\mathrm{moved}10\mathrm{kms}. \\ \mathrm{Again}\mathrm{he}\mathrm{travelled}200\mathrm{km}\mathrm{distance}\mathrm{to}\mathrm{returned}\mathrm{back}\mathrm{to}\mathrm{his}\mathrm{village} \\ \mathrm{at}\mathrm{the}\mathrm{speed}\mathrm{of}50\mathrm{km}/\mathrm{hr} \\ \mathrm{Therefore}, \\ \mathrm{Time}\mathrm{taken}\mathrm{by}\mathrm{the}\mathrm{man}\mathrm{to}\mathrm{return}\mathrm{back}\mathrm{to}\mathrm{his}\mathrm{village}=\frac{200}{50}=4\mathrm{hours} \\ \mathrm{The}\mathrm{average}\mathrm{speed}\mathrm{of}\mathrm{the}\mathrm{man}=\frac{\mathrm{Total}\mathrm{distance}\mathrm{travelled}}{\mathrm{Total}\mathrm{time}\mathrm{taken}} \\ =\frac{200+200+10}{5+1+4} \\ =\frac{410}{10} \\ =41\mathrm{km}/\mathrm{hr} \end{gathered}$$


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