Leaky current

Electricity and Magnetism Level 3

The simplest RC circuit consists of a single resistor and capacitor connected around a loop. A capacitor initially charged to $100~\mbox{V}$ is connected in such a circuit and the voltage across the capacitor drops to $10~\mbox{V}$ in $5~\mbox{seconds}$ . A second identical resistor is then connected in parallel with the first resistor. How long does it take in seconds for the voltage across the capacitor to further drop to $1~\mbox{V}$ ?