question_answer

A man walks 1 km towards East and then he turns to South and walks 5 km. Again he turns to East and walks 2 km, after this he turns to North and walks 9 km. Now, how far is he from his starting point?

A) 3 km                            

B) 4 km

C) 5 km                

D) 6 km

Correct Answer: C

Solution :

The movements of the man are as shown in figure (A to B, B to C, C to D, D to E). Clearly, \[DF=BC=5\text{ }km.\] \[EF=(DE-DF)=(9-5)\,km=4\,km.~~~\] \[BF=CD=2\,km.\] \[AF=AB+BF=AB+CD~\] \[BF=CD=2km.\] \[=(1+2)\,km=3\,km\] \[\therefore \] Man's distance from starting point A             \[=AE=\sqrt{A{{F}^{2}}+E{{F}^{2}}}\]             \[=\sqrt{{{3}^{2}}+{{4}^{2}}}=\sqrt{25}=5\,km.\]