Rats, I am out of touch!

In my earlier post on the rats at Bukit Batok I made a conservative
guesstimate on how much it would cost to get rid of the rats problem.
Off hand someone suggested that it would cost $30k to get the job done.
And that was huge to cull 300 rats at $100 each. How wrong he was though
I too thought that would be reasonable, to kill a rat. $100 a piece!
 
Someone pointed to me that the Chinese