How much gas? Help quick!

[rockabilly13]

I'm racing my first Harescramble tommorrow and I'm riding a 05 trx450r. It's a 50 mile race how far can I get on a tank of gas? Can I do the whole thing on one tank or should I gas up halfway through?

[44oEX]

you should be ok to do 50 miles...a full tank will last for 1-1.5 hour