First, we find the total of two-headed Jolos by subtracting the total 140 and the total of one-headed 75.
[tex]140-75=65[/tex]
There are 65 two-headed Jolos in total.
Then, we find the number of two-headed green Jolos by subtracting the total of two-headed 65 and the number of two-headed purple Jolos.
[tex]65-45=20[/tex]
There are 20 two-headed green Jolos.
At last, we sum the one-headed and two-headed green Jolos to find their total
[tex]30+20=50[/tex]
There are 50 green Jolos in total.
The right answer is B.