Final answer:
The average velocity of the balloon in the last five seconds is 0.56 m/s towards the east.
Step-by-step explanation:
To find the average velocity of the balloon in the last five seconds, we need to calculate the total displacement and divide it by the total time taken. The balloon initially drifts 45m towards the east in 4 seconds, and then flies 40m towards the west in the next 5 seconds. The total displacement is the sum of these distances, which is 45m - 40m = 5m towards the east. The total time taken is 4 seconds + 5 seconds = 9 seconds. Therefore, the average velocity of the balloon in the last five seconds is 5m/9s = 0.56 m/s towards the east.