Science and Mathematics for Engineering 6th Edition by John Bird

Exercise 7

A train travels from station P to station Q, a distance of 50 kilometres at an average speed of 80 kilometres per hour. It then travels from station Q to station R, a distance of 30 kilometres in 30 minutes. Finally, it travels from station R to station S at an average speed of 72 kilometres per hour in 45 minutes. Determine (a) the time taken to travel from P to Q, (b) the average speed of the train from Q to R, (c) the distance from R to S, and (d) the average speed of the whole journey from P to S.