Overall, this means the Lexus RX 350 can traverse roughly 23.5 miles per gallon of gas, regardless of the driving conditions—not exactly phenomenal, but not bad either.
Of course, fuel efficiency decreases slightly if your Lexus RX 350 is equipped with all-wheel drive functionality, but not by much—Lexus RX 350s with AWD average 19 MPG in the city and 26 MPG on the highway, for a combined average of 22 MPG.
Hopefully, this helps with your decision-making!