Please, solve it by an expert, not by the library!

In the fixed income market, there are two types of bonds:

Bond A:

Newly issued coupon bond

Fixed coupon rate of $5\mathrm{.}0\%$

Nominal value of $1000$ Euros

Maturity period of $6$ years from today

Redeemed in the form of annuity payments, with the first payment one year from now

Current market price: $1023\mathrm{.}79$ Euros

Bond B:

Perpetual bond

Next coupon payment of $45$ Euros to be made in one year

Coupon payments will decrease by $0\mathrm{.}50\%$ each year

What is the duration of Bond $B?$

$[$NB$!$ Please provide your answer with two decimal places. E$.$g$.$ if the answer is $123\mathrm{.}456$ then please type $123\mathrm{.}46]$

Answer: