A) 12 km
B) 15 km
C) 16 km
D) 18 km
Correct Answer: B
Solution :
The movements of the person are as shown in figure Clearly, \[AB=3\,km,\] \[BC=3AB=(3\times 3)km\] \[=9\,km\] \[CD=5AB=(5\times 3)km\] \[=5\,km\] Draw \[AE\bot CD\] Then, \[CE=AB=3\text{ }km\] and \[AE=BC=9\,km\] \[DE=(CD-CE)=(15-3)\,km=12\,\,km\] In \[\Delta AED,\] \[A{{D}^{2}}=A{{E}^{2}}+D{{E}^{2}}\] \[\Rightarrow \] \[AD=\sqrt{{{9}^{2}}+{{(12)}^{2}}}km=\sqrt{225}\,\,km\] \[=15\,\,km\] \[\therefore \] Required distance \[=AD=15\,km\]You need to login to perform this action.
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