A cab driver charges a 15 flat fee and 1.50 per mile. How many miles can you go with 30 dollars

Since it's 1.5 dollars per mile, you add 1.5 dollars for every mile and the amount of money total is 1.5m if m represents the amount of miles. In addition, since the flat tax is 15, you add 15 to it to get 1.5m+15. After that, since you only have 30 dollars, the amount of money is 30=15+1.5m. Subtracting 15 from both sides, we get 15=1.5m. Lastly, we divide both sides by 1.5 to get m=10