If half of a number is 3, then twice the number will be
Let's check whether you read the question. Also, did you answer the right question?
Standardized tests usually have time limits. Errors often come from rushing to an answer.
"If half of a number is 3" then the number must be 6.
Now, "twice the number will be" 12.
(Ha !! Did anyone say 6 ?)