Dottie,

How much did you pay for the gas? That should tell you how much gas you
had in the gas cans. Sounds like you bought around 5 gal of gas at about
$4/gal so you should have spent $20 or so. If you only bought 1/4 of a tank
you would have spent around $5.
I'd bet the fuel gauge is no good.

Dave M.