Barnes Enterprises has bonds on the market making annual payments, with 15 years to maturity, a par value of $1,000, and a price of $959. At this price, the bonds yield 8.8 percent. What must the coupon rate be on the bonds? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) Coupon rate???

Need the formula to answer in N= I/y= PV= etc

note: the coupon rate is not 82.97%