Let \(l\) be the length of a train. This particular train is on its way through the Himalayas, or at least a tunnel underneath the Himalayas. Fear not, however, because the stretch of tunnel that the train goes through is only 300 meters. It takes the train 20 seconds to completely pass in and out of the tunnel. One of the stationary ceiling lights in the tunnel is above the train for exactly 10 seconds. If the train is travels at a constant speed of \(s\) meters per second, find \(s+l\).