What is the duration of a bond with four years to maturity and a coupon of 8.6

Question:

What is the duration of a bond with four years to maturity and a coupon of 8.6 percent paid annually if the bond sells at par?

Coupon
A coupon or coupon payment is the annual interest rate paid on a bond, expressed as a percentage of the face value and paid from issue date until maturity. Coupons are usually referred to in terms of the coupon rate (the sum of coupons paid in a... Maturity
Maturity is the date on which the life of a transaction or financial instrument ends, after which it must either be renewed, or it will cease to exist. The term is commonly used for deposits, foreign exchange spot, and forward transactions, interest...