Those with correct answers
There are 5 gears each spinning independtly on a spindel at their own inderpendent but constant speed. Each geaer has a little red mark on it. Disk A spins at 1 revolution every 7 minutes; Disk B 1 revolution every 13; Disk C 1 every 17; Disk D 1 every 19; Disk E 1 every 23 minutes. How long will it take all red marks on the 5 gears point in the same direction in minutes (from when they all start simultaneously) AND when Disk A is pointing in the same direction it was pointing after 2 minutes; Disk B is pointing in the same direction it was after 3; Disk C after 4; Disk D after 7 and Disk E after 9.
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