Consider the following sum : ● + 1● + 2● + ●3 + ●1 = 21●. In the above sum, ● stands for
A
4
B
5
C
6
D
8
Correct Answer: Option D
Explanation
To solve this elegantly, we look at the question through the lens of a student who has analyzed the 2016 and 2017 papers. Those papers taught us to pay special attention to the 'units place' or 'end with' c