Answer:
Robin can clean 9828 rooms in 9 days
Explanation:
Since Robin can clean 727272 rooms in 666 days, we can find how many rooms she can clean in 1 day by dividing 727272 by 666
number of rooms cleaned by Robin in 1 day = 727272 rooms/666 days = 1092 rooms/day
We can then find how many rooms she can clean in 9 days by multiplying 1092 by 9
1092 rooms/day * 9 days = 9829 rooms