Hes not dumb, hes obviously just started out, so the least we can do is give the guy a hand yeah?
Make sure your chain is nice and oiled and make sure your brakes are not binding on your rims when you ride, if this is happeneing its slowing you down already!
Count how many teeth are on your chainring (that spiky thing on your crank that your chain wraps around) You can buy these in all saizes, from 12 to 48 tooth, so obviously the more teeth there is, the harder it will be to pedal but the faster you will go.
Other than that, just keep niking. After time you will develop your leg muscles a lot more and you will be able to push harder.
I know this sounds dumb, but try doing stretching exercises before a days ridin too. I ride Flatland, and theres bothing worse than having cramp halfway though the day.
Hope this helps.
Oh yeah, and if you eat more weaties, that will probabaly work too