Expensive Sheep

A farmer bargained with a gentleman for a dozen sheep (at 2 dollars per head) which were to be picked out of a dozen; but being long choosing them, the gentleman told him that if he would give him a cent for every different dozen which might be chosen out of the two dozen, he should have the whole, to which the farmer readily agreed. Pray what did they cost him?

Source: Nicholas Pike, A New And Complete System of Arithmetic, 1809

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