Jose and maris work for different car dealerships. jose earns a monthly salary for $3,500 plus 6% commission on sales. maris earns a salary of $4000 plus 4% commission of sales. above what value of sales are jose's monthly earnings more than those of maris?

Maris earns ($4,000 - $ 3,500 = ) $500 dollar more than Jose in salary, but Jose gets (4% - 2% =) 2 percentage point more in commissions. So for Jose to make more money than Maris 2% of the sales value has to be more than 500$. If 2% is 500$ than 100% is (500 / 2% * 100%) = 25,000$. So when the value of sales exceeds 25,000$ Jose will make more money than Maris.

The answer is 225 miles per 4.5 hours. hope this ; )