Arranged the following sources of funding:

• $200,000 from a five year fixed interest loan whose annual loan payments are $48,126.91
• $250,000 from a 5 year zero-coupon bond with a face value of $350,000
• $300,000 from an ordinary share issue where a dividend of $18,000 will be paid in one year and is expected to grow at 3% per annum
• $250,000 from a 5 year coupon-paying bond issue who coupon rate is 7% and face value is $250,000

How do you work out what is the discount rate given above sources of financing?