1.  If 7 spiders make 7 webs in 7 days, then 1 spider will make 1 web in how many days?
A. 1
B. 7/2
C. 7
D. 49

Answer: Option C

Explanation:

Let the required number days be x.

Less spiders, More days (Indirect Proportion)

Less webs, Less days (Direct Proportion)

Spiders 1 : 7 :: 7 : x
Webs 7 : 1

1 x 7 x x = 7 x 1 x 7

x = 7.