Common Information
A boy is roaming on the roof of his house observes that the insects are there in bunches. He found '$p$' insects on day 1. On day two, the number of insects doubled and he takes out '$q$' insects and kills them. On the third day again, the insects left is doubled and he again takes out '$q$' insects and kill them. On the fourth day also he found the same, insects left is doubled and he takes out '$q$' insects again. He is surprised to find that there are no insects left on his roof.
Q16. 
Common Information Question: 1/3 If the number of insects on the roof, on day 1 is 63, then the number of insects that they kill on the fourth day is: 
A.  63 

B.  90 

C.  72 

D.  75 
Q19. 
In a certain water body, 50 fish were caught, tagged and released to the same water body. A few days later, 50 fish were caught again, of which 2 were found to have been tagged on previous occasion. If the percent of tagged fish in the second catch approximates the percent of tagged fish in water body, what is the approximate number of fish in the water body: 
A.  10,000 

B.  625 

C.  1250 

D.  2500 
Q20. 
A transport agency has 5 carriers, each of capacity 15 tonnes. The carriers are scheduled such that the first carrier makes a trip every day, the second carrier makes a trip every second. The third makes a trip every third day and so on. Find the maximum number of times in a year that it is possible to dispatch a total shipment of 75 tonnes in a single day. The operation starts on the 7th January 2010 and continue till the end of the year (31st December 2010) without any holiday. 
A.  7 

B.  6 

C.  5 

D.  8 