We have a taxi ride where the total fare is $3 plus $2 for every mile travelled plus a $1 tip and the whole thing is $20.
Let's first write a formula that expresses the cost of the ride:
Total cost
=
Flat fee
+
Mileage
+
Tip
Now let's drop in what we know:
20=3+2(miles)+1
- we know the total cost of 20, the fee of 3, the tip of 1 and the cost per mile of 2. The only thing we don't know is the number of miles. So let's solve for that.
First we subtract 3 and 1 from both sides and get:
