The graph shows the speed of a train during the first 60 seconds of motion - OCR - GCSE Maths - Question 15 - 2019 - Paper 4

To determine the speed of the train after 9 seconds, we refer to the speed-time graph provided. From the graph:

1. At 0 seconds, the train begins to accelerate until it reaches a speed of 20 m/s at around 15 seconds.
2. From 15 seconds onwards, the speed remains constant at 20 m/s until the 45-second mark.
3. After 45 seconds, the train starts decelerating.

Since 9 seconds falls within the interval of acceleration, we can see that at 9 seconds, the train is still in the process of speeding up and has reached a speed just below 20 m/s at that point (which can be estimated or calculated based on the linear increase in speed).

Thus, the approximate speed of the train after 9 seconds is around 12 m/s.