If 7 spiders make 7 webs in 7 days, then 1 spider will make 1 web in how many days?
1
$ \dfrac{7}{2} $
7
49
Explanation:
Let the required number days be $ x $.
Less spiders, More days (Indirect Proportion)
Less webs, Less days (Direct Proportion)
$\therefore$ 1 x 7 x $ x $ = 7 x 1 x 7
$\Rightarrow x $ = 7.