Answer
83 days.
Work Step by Step
Use equation 17–7 on page 483.
$$Q=CV$$
$$\Delta Q=C\Delta V$$
$$\Delta t=\frac{\Delta Q}{\Delta Q/\Delta t}=\frac{ C\Delta V }{\Delta Q/\Delta t}$$
$$=\frac{ (1200F)(6.0V)}{0.001C/s}=7.2\times10^6 s$$
Convert to days.
$$(7.2\times10^6 s) \frac{1d}{86400s}=83d$$
