A bond with a coupon rate of $5\%,$ have a face value of $$100.$ The market price of bond currently is $$91.$ What is the YTM$,$ if the bond have $4$ years to maturity?

Market price of bond $($B$0)$ is $=$$$91$

Coupon rate $=5\%$ Coupon value $=5\%$$$100=$$$5$

Years to maturity $=4,$ face value $=$$$100$