You are buying a property for $250,000. If you borrow 80% of the value, the interest is

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You are buying a property for $250,000. If you borrow 80% of the value, the interest is 7.5%, but if you go up to 95%, interest increases to 8.75%. What is the cost of borrowing additional 10%? How do you decide whether throwing in additional cash would be beneficial ? Please solve on excel and show formula