To solve the equation \( 225 + (-10t) = 50 + 15t \), we can first simplify it:
\[ 225 - 10t = 50 + 15t \]
Next, we can move all terms involving \( t \) to one side and constant terms to the other side. Let's add \( 10t \) to both sides:
\[ 225 = 50 + 15t + 10t \]
This simplifies to:
\[ 225 = 50 + 25t \]
Now, subtract \( 50 \) from both sides:
\[ 225 - 50 = 25t \]
This simplifies to:
\[ 175 = 25t \]
Next, divide both sides by \( 25 \):
\[ t = \frac{175}{25} = 7 \]
Thus, the solution is:
\[ \boxed{7} \]