What least number should be added to 1536, so that the sum is completely divisible by 21?
Pick:
A) 16
B) 17
C) 18
D) 19
E) 20
1536÷21=73 Reminder -3   3+18= 
<gadget id="calculator">3+18</gadget>
<output>21</output>
21   Hence 18 should be added to 1536 so that the sum will be divisible by 21   answer :18
<result>C</result>
What least number should be added to 1536, so that the sum is completely divisible by 21?