2 gears one with 12 teeth and other one with 15 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?  Choose the correct choice from the following choices:
A) 5  B) 12  C) 48  D) 60  E) 120
Assume that the distance b/w gears be 1cm.   Then the circumference of 1st gear is 12cm and 2nd gear is 15cm.   So.   The LCM of 12 and 15 is 60.   So,   1st gear has rotate  60/12= 
<gadget id="calculator"> 60/12</gadget>
<output>5</output>
5(Smaller Gear)   2nd gear has rotate  60/15= 
<gadget id="calculator"> 60/15</gadget>
<output>4</output>
4(Bigger Gear)   So,   The answer is 5.   5NSWER:5
<result>A</result>
2 gears one with 12 teeth and other one with 15 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?