Answer:
4.5 years
Explanation:
the change in price = $970 - $950 = $20
the change in rate of return = 7.7% - 8.2% = -0.5% or -0.005
to determine the duration of the bond we can use the following formula:
duration = (Δ price / price) / [Δ rate / ( 1 + rate)]
= ($20 / $970) / [-0.005 / ( 1 + 0.077)] = 0.0206 / (-0.0046) = -4.48 years ≈ 4.5 years (remaining time is positive)