How do I stop excessive fuel consumption of my 2003 Toyota Camry? on 2003 Toyota Camry

My 2003 Toyota Camry consumes so much fuel. I travel a distance of about 50km daily (to and fro 50km)from Monday to Friday and my full tank of fuel is exhausted within one week.

2 answers
What about the weekend? Check engine light on? Need to know how many miles driven on a full tank, not how much you drive 5 days a week!
scan codes and post so we can adv