Answer:
The missing marks are 3, 3, and 5.
Step-by-step explanation:
Since the mode is 3, that means it's the number that occurs most often. The numbers 1 and 2 occur twice so there must be at least 3 3's on the list. But since the mean is 2.9, the third mark cannot be a 3 because it will make the mean only 2.7 so the 3rd mark can be either a 4 or a 5. Using 5 will make the mean 2.9. I take it that you know how to make a bar graph for this problem.
