Atrain is moving 30.0 km/h [w] relative to the ground. a passenger on the train is walking towards the back of the train at 5.0 km/h [e] with respect to the train. what is the passenger’s velocity relative to the ground?

The first-order reaction a→2b+c has rate constant 0.538 s−1. if the initial concentration of a is 0.867 mol l−1, what is the half-life of the reaction in seconds? remember to use correct significant figures in your answer (round your answer to the nearest hundredth). do not include units in your response.