Does this sound right? 13.07mpg(15% highway 85%city). 27% of the time i was being conservative and 40% aggressive(flooring the car

, going uphill alot, 80 on the hwy) 33% was regular driving characteristics. Another factor may be the tires. The tires are all different ones and all their tread conditions vary (one new tire,2 poor ones and one REALLY BAD ONE). The new tire is in the rear, the worst tire is on the front passenger side. The Psi was around 26 for all except for the really worn out tire which was 43psi

. I also have a poor bumper( only top part is intact; bottom is missing or dangling in pieces) I also have a big dent on driver side fender. So friends, is 13mpg average plausible? the car has 152k miles on it.