Question

A cyclist goes 40 km towards East and then turning to right he goes 40 km. Again he turn to his left and goes 20 km. After this he turns to his left and goes 40 km, then again turns right and goes 10 km. How far is he from his starting point ?

• A. 150 km
• B. 60 km
• C. 70 km
• D. 50 km

Answer 1

Answer:

C. 70 km

The cyclist is 70 km away from his starting point.

• East: He moves 40 km East.
  (Current position: 40 km East)

• Right turn (South): Turning right means heading South for 40 km.
  (Current position: 40 km East, 40 km South)

• Left turn (East): Turning left from South means heading East again for 20 km.
  (Current position: 60 km East, 40 km South)

• Left turn (North): Turning left from East means heading North for 40 km. This completely cancels out his previous 40 km South movement, bringing him back in line horizontally with the starting point.
  (Current position: 60 km East, 0 km North/South)

• Right turn (East): Turning right from North means heading East for one final stretch of 10 km.
  (Current position: 70 km East, 0 km North/South)

Since his final position is directly East of the starting point, you simply add up the net distances traveled eastward: 40 km + 20 km + 10 km = 70 km.