AMC 12 2013a Problem 5

Tom, Dorothy, and Sammy went on a vacation and agreed to split the costs evenly. During their trip Tom paid $$105$, Dorothy paid $$125$, and Sammy paid $$175$. In order to share the costs equally, Tom gave Sammy $t$ dollars, and Dorothy gave Sammy $d$ dollars. What is $t-d$?

\textbf{(A)}\ 15 \textbf{(B)}\ 20 \textbf{(C)}\ 25 \textbf{(D)}\ 30 \textbf{(E)}\ 35