Answer:
7 miles
Step-by-step explanation:
If there is a $2.50 fix charge, that means you will have to pay $2.50 no matter how many miles you go. So automatically, subtract $2.50 from the $20 that you have, which will now be $17.50 left.
Now for every mile its $2.50 charged. So $2.50 for one mile, $5 for two miles $7.50 for 3miles, $10..$12.5...keep adding $2.50 untill you get to the maximum amount $17.50. You will discover that you added 2.50 7 times until you got 17.50 So you can only go 7 miles. Or to do it even quicker just divide 17.5/2.50=7