Workers in a fixed daily rotation (pairs or alternate days): days to finish

This type of question, asked 2 times: 8 Aug 2022 Tier II, 7 Mar 2023 Tier II. All 2 questions below, oldest first.

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Question 1
8 Aug 2022 Tier II
100 $A alone can do a work in 11 days. B alone can do the same work in 22 days. C alone can do the same work in 33 days. They work in the following manner: Day 1: A and B work. Day 2: B and C work. Day 3: C and A work. Day 4: A and B work. And so on. In how many days will the work be completed?$
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Question 2
7 Mar 2023 Tier II
11 $P, Q and R can finish a work in 5 days, 10 days, and 15 days, respectively, working alone. P and Q works on first day, P and R works on second day and P and Q works on third day and son on till the work is completed. In how many days the work will be completed?$
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Question 1