Facing the east R walks straight 4 km, turns left and walks 3 km and again turns left and walks 4 km. How far is R now from the starting point?

examrobotsa's picture
Q: 5 (CAPF/2012)
Facing the east R walks straight 4 km, turns left and walks 3 km and again turns left and walks 4 km. How far is R now from the starting point?

question_subject: 

Maths

question_exam: 

CAPF

stats: 

0,36,8,3,36,4,1

keywords: 

{'km': [0, 0, 2, 1]}

In this question, R initially faces east and walks straight for 4 km. Then, R turns left and walks another 3 km. After that, R turns left again and walks 4 km.

To determine how far R is from the starting point, we can consider the displacements made in each direction. Since R turns left twice, it essentially moves in a counter-clockwise direction.

The initial displacement of 4 km east is offset by a subsequent displacement of 4 km west (when R turns left for the first time). This means that R is back to its starting point horizontally.

Next, R moves 3 km in the opposite direction of its initial displacement, which means it is moving north. Finally, R turns left and moves 4 km in the opposite direction again, which means it is moving west.

So, R ends up 3 km north and 4 km west from its starting point. This establishes a right-angled triangle with legs measuring 3 km and 4 km. By using the Pythagorean theorem (a^2 + b^2 = c^2) to find the hypotenuse (c), which is the distance from R to the starting point, we get:

c^2 = 3^2