An entrepreneur owns a large number of shares of a corporation of which she was one of the original founders. She is considering the tax implications of giving a large gift to her children using the earnings generated by her ownership of this corporation. The corporation pays taxes at a rate of $21\%$ on all profits. After these profits are taxed at the corporate tax rate, they are distributed, as dividends, to the entrepreneur, who then pays income taxes at a marginal rate of $35\%$ on her dividend income $($this is so$-$called double taxation$).$ If she uses these dividends to give a gift to her children, her children would then pay income taxes on this gift at a rate of $15\%.$ What would be the effective tax rate on corporate profits collected by the entrepreneur, and given to her children, including the effects of all of these taxes?