I need assistance calculating the lowest average cost of capital, please

WestGas Conveyance, Inc. WestGas Conveyance Inc. is a large US natural gas pipeline company that wants to raise $120 million to finance expansion WestGas wants a capital structure that is 50% debt and 50% equity Its corporate combined federal and state income tax rate is 39% WestGas finds that it can finance in the domestic US capital market at the rales listed in the popup window Both debt and equity would have to be sold in multiples of $20 million and these cost figures show the component costs, each of debt and equity if raised 50% by debt and 50% by equity A London bank advises WestGas that US dollars could be raised in Europe at the following costs, also in multiples of $20 million, while maintaining the 50/50 capital structure Each increment of cost would be influenced by the total amount of capital raised That is, if WestGas first borrowed $20 million in the European market at 7% and matched this with an additional $20 million of equity, additional debt beyond this amount would cost 13% in the United States and 12% in Europe The same relationship holds for equity financing a. Calculate the lowest average cost of capital for each increment of $40 million of new capital where WestGas raises $20 million in the equity market and an additional $20 in the debt market at the same time b. If WestGas plans an expansion of only $60 million how should that expansion be financed? c. What will be the weighted average cost of capital for the expansion? Data Table (Click on the icon to import the table into a spreadsheet) Costs of Raising Capital in the Market Up to $40 million of new capital S41 million to $80 million of new capital Above $80 million Cost of Domestic Equity 11% 19% 21% Cost of Domestic Debt 8% 13% 17% Cost of European Equity 13% 17% 22% Cost of European Debt 7% 12% 18% Print Done Done