2 gears one with 12 teeth and another with 14 teeth are engaged with each other. One tooth 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, will the marked teeth in the two gears come into contact for the first time?

Correct Option - A

ExplainationLet the distance between two teeth be 1 cm. Circumference of first gear = 12 cm Circumference of second gear = 14 cm LCM(12,14) = 84 To cover 84 cm, no. of rotations taken by the first gear = 84/12 = 7