To solve this problem, we can use the concept of work rates.
Let's assume that the rate at which one painter can complete the job is 1 unit per day. Therefore, the combined work rate of 3 painters is 3 units per day.
We are given that the job takes 29 days to complete with 3 painters. Therefore, the total work required to complete the job is 3 units/day * 29 days = 87 units.
Now, let's consider the scenario where 6 more painters join the team after 2 days. This means that for the first 2 days, only the initial 3 painters were working.
In these 2 days, the work completed by the initial 3 painters is 3 units/day * 2 days = 6 units. Therefore, the remaining work to be completed is 87 units - 6 units = 81 units.
Now, the combined work rate of 9 painters is 9 units/day.
To find the number of days required to complete the remaining work, we can divide the remaining work by the combined work rate of 9 painters:
Remaining work / Combined work rate = 81 units / 9 units/day = 9 days.
Therefore, the additional number of days required to complete the job is 9.
The correct answer is C) 9.