When toys are grouped into 12 and 18, always 3 toys remain ungrouped. What is the minimum number of toys to be added so that when they are grouped into 7, no toys will remain ungrouped ?  Answers
A) 0
B) 1
C) 2
D) 3
E) 4
T= 12a+3 = 18b + 3   2a=3b --&gt; min (a,b) = (3,2)   So minimum number of toys --&gt; 12*3+3 = 39   When toys are grouped into 7, 4 will remain ungrouped so in order to make another group of 7 toys --&gt;   7-4   --  12*3+3= 
<gadget id="calculator">  --  12*3+3</gadget>
<output>39</output>
39   When toys are grouped into 7, 4 will remain ungrouped so in order to make another group of 7 toys --&gt;    7-4= 
<gadget id="calculator"> 7-4</gadget>
<output>3</output>
3 toys at least to be added.   ANSWER: 3
<result>D</result>
When toys are grouped into 12 and 18, always 3 toys remain ungrouped. What is the minimum number of toys to be added so that when they are grouped into 7, no toys will remain ungrouped ?