If 10 spiders make 5 webs in 5 days, then how many days are needed for 1 spider to make 1 web?
Options:
A) 10	B) 9	C) 5	D) 15	E) 20

Rationale: "explanation : let , 1 spider make 1 web in x days . more spiders , less days ( indirect proportion ) more webs , more days ( direct proportion ) hence we can write as ( spiders ) 10 : 1 ( webs ) 1 : 5 } : : x : 5 â ‡ ’ 10 ã — 1 ã — 5 = 1 ã — 5 ã — x â ‡ ’ x = 10 answer : option a"
Answer: A