2 gears one with 12 teeth and other one with 14 teeth are engaged with each other. One teeth in smaller and one tooth in bigger are marked and initially those 2 marked teeth are in contact with each other. After how many rotations of the smaller gear with the marked teeth in the other gear will again come into contact for the first time? Options.
A) 6  B) 7  C) 8  D) 9  E) 2
Assume the distance between the teeth is 1 cm. Then the circumference of first gear is 12 cm and the second is 14 cm.   Now LCM (12, 14) = 84. So to cover 84 cm, the first gear has to rotate 84128412 = 7 rounds (the second gear rotates 84 / 14= 
<gadget id="calculator">84 / 14</gadget>
<output>6</output>
6 rounds as it is bigger)   Correct Option : 6
<result>A</result>
2 gears one with 12 teeth and other one with 14 teeth are engaged with each other. One teeth in smaller and one tooth in bigger are marked and initially those 2 marked teeth are in contact with each other. After how many rotations of the smaller gear with the marked teeth in the other gear will again come into contact for the first time?