BMW UK ltd$.$ expects to keep free cash flow in the coming year of $20$ million,

and such free cash flow is estimated to grow at a rate of $8\%$ per year indefinitely. The firm has a cost of equity of $16\%,$ a cost of debt of $15\%.$ The firm also maintains a target debt to equity ratio of $0\mathrm{.}68.$ If the corporate tax is $24\%,$ calculate the value of the firm$$s interest tax shield.