A company issues a $1,000 perpetual bond. The current rate is 6%. Next period, the ratewill change to either 4% or 10%, with equal probability. The bond is callable at the endof the first year only, for a price of $1,117.90. What is the coupon amount, if the bond sells at par?

The answer is 83.51 and i cant figure out how to get this answer.