If 7 spiders make 7 webs in 7 days, then how many days are needed for 1 spider to make 1 web?

7 spiders make 7 webs in 7 days.
∴ 1 spiders make 7 webs in 7 x 7 days.
∴ 1 spiders make 1 webs in 7 x 7 / 7 days.
∴ 1 spiders make 1 webs in 7 days.