Answer
$ 5\%$
Work Step by Step
The bond costs (now) $PV$=1000
Using the simple interest formula, the total interest
over a period of t=5 years
is
INT=$PV\cdot rt$
solving for r, (divide with $PV\cdot t$)
$r=\displaystyle \frac{INT}{PV\cdot t}=\frac{250}{1000\cdot 5}= 0.05$