Men and women: two combined crews' times give one person's rate

This type of question, asked 2 times: 15 Nov 2020 Tier II, 29 Jan 2022 Tier II. All 2 questions below, oldest first.

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Question 1
15 Nov 2020 Tier II
100 $Three men and 4 women can do a piece of work in 7 days, whereas 2 men and 1 woman can do it in 14 days. Seven women will complete the same work in:$
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Question 2
29 Jan 2022 Tier II
60 $4 men and 5 women can complete a work in 15 days, whereas 9 men and 6 women can complete it in 10 days. To complete the same work in 7 days, how many women should assist 4 men?$
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Question 1