At a furniture manufacturer, worker A can assemble a shelving unit in \( 5 \) hours. Worker B can assemble the same shelving unit in \( 3 \) hours. Which equation can be used to find \( t \) , the time in hours it takes for worker A and worker B to assemble a shelving unit together?
\(5 t + 3 t = 1 \)
\( \frac { 1 } { 5 } t - \frac { 1 } { 3 } t = 1 \)
\( \frac { 1 } { 5 } t + \frac { 1 } { 3 } t = 1\)