These three together form total market, so here we have to add up everything to know volume of the market
A+B+C = 1,275,000 is the total market
Then we have to calculate individual market share
which would eb 1) 28.2%, 2) 50.9%, 3) 20.8%
This can be calcualated by simple percetage calculation. ( 1275000-360000/1275000*100)-100 will give what share each has.
Then we apply HHI formula
HHI = s1^2 + s2^2 + s3^2 + ... + sn^2
HHi is nothing but squaring of each of the percentages and adding them up
(28.2)2 +(50.9)2 +(20.8)2
812+2590+432 = 3834
HHI of 3834 shows it is highly competitve market.
