question_answer

A girl walks \[\text{5}00\,\text{m}\] towards East and then \[1200\,\text{m}\] towards North. Find her distance from the starting point (cbse 2016)

A) \[1100\,\text{m}\]

B) \[1200\,\text{m}\]

C) \[1300\,\text{m}\]

D) \[1400\,\text{m}\]

Correct Answer: C

Solution :

[c] Let a girl starts from point 0 and walks \[500m\]towards east, then \[1200m\]towards north.

By Pythagoras thorem,

\[O{{N}^{2}}=O{{E}^{2}}+N{{E}^{2}}\]

\[={{(500)}^{2}}+{{(1200)}^{2}}\]

\[=250000+1440000\]

\[=1690000\]

or         \[ON=\sqrt{1690000}\]

\[=1300\,m\]

Hence, the girl is 1300 om far from the starting point.