If 9 spiders make 9 webs in 9 days, then how many days are needed for 1 spider to make 1 web?
Select the correct option:	A) 5 days	B) 7 days	C) 8 days	D) 9 days	E) 6 days
Let, 1 spider make 1 web in a days.   More spiders, Less days (Indirect proportion)   More webs, more days (Direct proportion)   Hence we can write as   (spiders)9:1   }::a:9   (webs)1:9   ⇒7×1×7=1×7×a   ⇒a=7   ANSWER:7 days
<result>B</result>
If 9 spiders make 9 webs in 9 days, then how many days are needed for 1 spider to make 1 web?