Rohini walks 10 km north and turns right. She walks 10 km and then turns left. She walks 10 km and then turns right and walks 10 km more. How far (in km) is she from her starting point?

Options

A. 20
B. `10sqrt(2)`
C. `20sqrt(2)`
D. 40

Answer

B

Explanation

`AE = sqrt((AF)^(2) + (FE)^(2))`
` = sqrt((20)^(2) + (20)^(2))`
` = sqrt(400 + 400) = sqrt(800)`
` = sqrt( 400 xx 2) = 20 sqrt(2) km`.