How many smokes?

Mr. Puffem, a heavy smoker for many years, finally decided to stop smoking altogether. "I'll finish the twenty-seven cigaretees I have left," she said to herself, "and never smoke another one."
It was Mrs. Puffem's practice to smoke exactly two-thirds of each cigarette. It did not take her long to discover that with the adi of some cellophane tape she could stick three butts together to make a new cigarette. With 27 cigarettes on hand, how many cigarettes can she smoke before she gives up the weed forever?

Solution:

After smoking 27 cigarettes, she patched together the butts to make 9 more, and after smoking these, she had enough butts for 3 more smokes; then with the final 3 butts she made one final cigarette, total : 40 cigarettes