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题库 / OG2017Q-DS-259
What is the number of 360-degree rotations that a bicycle wheel made while rolling 100 meters in a straight line without slipping?
(1) The diameter of the bicycle wheel, including the tire, was 0.5 meter.
(2) The wheel made twenty 360-degree rotations per minute.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
题目分析：
自行车每转360度，前进的距离为车轮的周长。
（1） 直径d=0.5m，所以周长为πd≈1.57m，所以前进100m，旋转360度的圈数为100/1.57≈63.7圈，题目得解。
（2） 转圈的多少只与半径有关，与转速无关，因此条件2无法解题。
因此，本题答案为（A），仅条件1可以解题，条件2不行。