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Question

Mr. Yanki starts from Point A and drives 17 km towards the South. He then takes a right turn, drives 19 km, turns right and drives 29 km. He then takes a right turn and drives 15 km, turns right drives 1 km. He then takes a left turn drives 6 km. He takes a final right turn, drives 11 km and stops at Point P. How far (shortest distance) and towards which direction should he drive in order to reach Point A again? (All turns are 90 degrees turns only unless specified.)

The correct answer is
2 km to the West

Mr. Yanki's Driving Problem: Finding the Return Path

This problem involves tracking movement based on directions and distances to find the shortest path back to the starting point. We can solve this by treating the movements as vectors or by using a coordinate system.

Understanding Mr. Yanki's Movements

Let's break down each step of Mr. Yanki's journey. We'll use a coordinate system where Point A is the origin (0, 0). We'll assume North corresponds to the positive y-axis and East corresponds to the positive x-axis. Therefore, South is the negative y-axis and West is the negative x-axis.

Tracking Position with Coordinates

We can track Mr. Yanki's position after each segment of his journey. A table helps visualize these changes.

Movement Segment Direction Driven Distance (km) Turn Made Facing Direction Coordinate Change (Δx, Δy) Current Position (x, y)
Start (Point A) - - - - (0, 0) (0, 0)
1 South 17 - South (0, -17) (0, -17)
2 West 19 Right West (-19, 0) (-19, -17)
3 North 29 Right North (0, 29) (-19, 12)
4 East 15 Right East (15, 0) (-4, 12)
5 South 1 Right South (0, -1) (-4, 11)
6 East 6 Left East (6, 0) (2, 11)
7 (Stop at P) South 11 Right South (0, -11) (2, 0)

Calculating Final Position

After all the movements, Mr. Yanki stops at Point P. Let's calculate the net displacement in the x (East-West) and y (North-South) directions:

  • Net East-West Displacement: Sum of x-changes = $0 + (-19) + 0 + 15 + 0 + 6 + 0 = 2$ km. This means Point P is 2 km East of Point A.
  • Net North-South Displacement: Sum of y-changes = $(-17) + 0 + 29 + 0 + (-1) + 0 + (-11) = 17 - 17 = 0$ km. This means Point P is on the same East-West line as Point A.

So, the final position of Point P relative to Point A is (2, 0).

Determining Return Path to Point A

Mr. Yanki is currently at Point P (2, 0) and needs to return to Point A (0, 0).

The required displacement vector from P to A is:

Displacement = (Target x - Current x, Target y - Current y)

Displacement = ($0 - 2$, $0 - 0$) = (-2, 0)

A coordinate change of (-2, 0) means moving 2 units in the negative x-direction.

  • The negative x-direction corresponds to the West direction.
  • The magnitude of the movement is $ \sqrt{(-2)^2 + (0)^2} = \sqrt{4} = 2 $ km.

Therefore, Mr. Yanki needs to drive 2 km towards the West to reach Point A again.

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Important Questions from Direction and Distance

  1. What is the direction of U with respect to P?

  2. What is the shortest distance between R and T?

  3. If a person walks 3m towards the North from point V, takes a right turn and walks for another 15m, which of the following points would he reach?

  4. In which direction is Amit facing at point F?

  5. What is the distance between the starting point and the end point?

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