The thing to look at here is when it states "The word “sum” means the result of adding two numbers."
We can eliminate [ The correct equation is n – 2.2 = 5 ] since its subtracting not adding.
Since, we know that right equation is [ n + 2.2 = 5 ], we can solve for n.
n + 2.2 - 2.2 = 5 - 2.2
n = 2.8
Therefore, the correct answers are answer:
The correct equation is n + 2.2 = 5.
The solution of the equation is n = 2.8.
Best of Luck!