(3)If a person purchasing goods commits an offence under clause (c) or clause (d) of section 50, the authority which granted him, or, as the case may be, is competent to grant him a certificate of registration under this Act, may, after giving him a reasonable opportunity of being heard by order in writing impose upon him by way of penalty, a sum not exceeding two and a half times the tax which could have been levied under this Act in respect of the sale to him of the goods, if the offence had not been committed.
