Taxi a charges $0.20 per mile and an initial fee of $4. taxi b charges $0.40 per mile and an initial fee of $2. write an inequality that can determine when the cost of taxi b will be greater than taxi a.

Well, for taxi A we have:

Cost of Taxi A = $ 0.20*X + $4
With "X" equal to "miles traveled".
For taxi B we have:
Cost of Taxi B = $ 0.40*X + $2
Then, when
Cost of Taxi B > Cost of Taxi A,

We Have:
$ 0.40*X + $2 > $ 0.20*X + $4

That is the inequality that you need!
Good luck!
M.