Let Cole's age be represented as \( c \) and Tina's age as \( t \). According to the problem, Cole's age is 3 years less than Tina's age, which can be expressed as the equation:
\[ c = t - 3 \]
We know that Cole is 18 years old, so we can substitute \( c \) with 18:
\[ 18 = t - 3 \]
To find Tina's age, we can rearrange the equation:
\[ t = 18 + 3 \] \[ t = 21 \]
Now we can verify our answer with the choices given. The equation \( t - 3 = 18 \) can be rearranged to \( t = 21 \), which matches with our calculation. Thus:
The correct answer is: A. The equation that represents this situation is \( t - 3 = 18 \). Tina is 21.