A person facing north turns 90° clockwise, then 180°, and then 90° anticlockwise. Which direction is the person now facing?

Question 27

MediumOriginal question

A person facing north turns $90^\circ$ clockwise, then $180^\circ$ , and then $90^\circ$ anticlockwise. Which direction is the person now facing?

NorthCorrect answerYour answerSouthCorrect answerYour answerEastCorrect answerYour answerWestCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

Starting from north, a $90^\circ$ clockwise turn faces east.
A $180^\circ$ turn reverses that, so the person now faces west.
From west, a $90^\circ$ anticlockwise turn goes west to south, because anticlockwise runs north, west, south, east.
The person ends up facing south.

Worth noting

The clockwise and anticlockwise quarter-turns cancel, so the $180^\circ$ turn alone decides the answer: the opposite of north is south. Seeing that first saves the whole trace.

Concept: Composing clockwise and anticlockwise turns
Typical timeTypical: 65 s
Your timeYours: —

The rule this testsTurns and facing

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Ten questions from Direction Sense, at your own pace.

A person facing north turns 90∘90^\circ90∘ clockwise, then 180∘180^\circ180∘, and then 90∘90^\circ90∘ anticlockwise. Which direction is the person now facing?

Explanation

A person facing north turns $90^\circ$ clockwise, then $180^\circ$ , and then $90^\circ$ anticlockwise. Which direction is the person now facing?