You just have to be creative and you can get whatever MPG you want!
I look at it this way: My 68 gets 10mpg
My bike gets 50mpg
added together they get 60mpg
divided by 2 = 30mpg
So looking at it that way, as long as I drive my bike and my truck an equal number of miles each week then I will be getting 30mpg out of each of them
