If 5 spiders make 2 webs in 8 days, then how many days are needed for 1 spider to make 1 web?
Pick one:	A) 10	B) 15	C) 30	D) 20	E) 16
Explanation:   Let, 1 spider make 1 web in x days.   More spiders, Less days (Indirect proportion)   More webs, more days (20irect proportion)   Hence we can write as   (spiders)5:1   (webs) 1:8}::x:2   â‡’5Ã—1Ã—8=1Ã—2 Ã— x   â‡’x=20   Answer: Option 20
<result>D</result>
If 5 spiders make 2 webs in 8 days, then how many days are needed for 1 spider to make 1 web?