A taxi service charges an initial fee of $5 plus $1.80 per mile. How many miles can you travel for $12

First you need to write an equation or an inequality.

5+1.80x<=12

the x here is how many miles you are paying for, now you just solve for x.

5+1.80x<=12

-5 - 5

1.80x<=7

/1.80 / 1.80

x<=3.8

you can travel only three whole miles, you do not have enough money to go four full miles.