First, you find what 20% of 10 gallons of gas would be. This will show how many gallons the car actually uses.
10 gallons x 20% =
10 x 0.20 =
2 gallons used
Then you subtract that number from the total 10 gallons to get how many gallons of gas would be wasted.
10 gallons - 2 gallons =
8 gallons of gas wasted
Although you walked (14+9)= 23 meters of distance, you ended up only 16.64 meters from where you started. That's your "displacement".
Velocity = (displacement / (time)
Velocity = (16.64m)/(180s)
Velocity = 0.0925 m/s roughly Southwest.
(That's about 3.6 INCHES per second. Apparently, you really NEED that mocha java and it's associated drug.)