Worker ants:110 / 2 = 55 ants. Male worker ants:55(.20) = 11. Female worker ants:55 - 11 = 44 ants.
This justifies what answer for what question? Q & A: 
Stephen has 110 ants in his ant farm. Half of the ants are worker ants, 20 percent of the worker ants are male. How many female worker ants are there?
44