Write an inequailty for the sentence. then solve th inequality..
fifteen less than a number is at most 6.

Elena and her husband marc both drive to work. elena's car has a current mileage (total distance driven) of 7,000 and she drives 21,000 miles more each year. marc's car has a current mileage of 20,000 and he drives 11,000 miles more each year. will the mileages for the two cars ever be equal? explain.