Concept: The question tests on the application of Profit/Loss Concepts.


Solution:
It is given that for every 60 cameras 54 make a profit and 6 make a loss.

=> 54/60 =9/10 cameras contribute to profit whereas 1/10 contributes to a loss.

Let there be 10 cameras priced at $10 each 
=>Total investment =10*10=100$

Total profit =(20% of 10)*9 =18$

Total loss = (50% of 10)*1 =5$

Hence effective profit = 18-5 =13 $

Profit% = Profit/CP(Investment)*100 

= 13/100)* 100 =13 % profit. (Option D)