Initially, a spinner points west. Chenille moves it clockwise 2 (1/4) revolutions and then counterclockwise 3 (3/4) revolutions. In what direction does the spinner point after the two moves?

AMC 8 2006 Problem 4

AMC8 2006 年第 4 题

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Initially, a spinner points west. Chenille moves it clockwise

2 \dfrac{1}{4}

revolutions and then counterclockwise

3 \dfrac{3}{4}

revolutions. In what direction does the spinner point after the two moves?

最初，转盘的箭头指向西边。Chenille 将它顺时针旋转

2\dfrac{1}{4}

圈，再逆时针旋转

3\dfrac{3}{4}

圈。两次转动后，箭头指向哪个方向？

正确答案 · Correct Answer

Solution 1

If the spinner goes clockwise

2 \dfrac{1}{4}

revolutions and then counterclockwise

3 \dfrac{3}{4}

revolutions, it ultimately goes counterclockwise

1 \dfrac{1}{2}

which brings the spinner pointing

\text{east}

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