For this case we must find the sentence that best describes the equation given by:
![78 + y = 105](https://img.qammunity.org/2019/formulas/mathematics/middle-school/4fd7lthvz4p7b290mb80st2y4ifrrtxb6i.png)
It is observed that at 78 a number is added, which can be any, and the sum results in 105.
So, the sentence that best fits is:
The sum of 78 and a number is 105
Answer:
The sum of 78 and a number is 105
Option A