A group of mountain climbers set up a camp at a $3$ km altitude and experience a barometric pressure of $0.69$ atm. They discover that pure water boils at $90^{\circ}$C  and that it takes $300$ minutes to make a "three-minute" egg. What is the ratio of rate constants at $100^{\circ}$C and at $90^{\circ}$C i.e $\dfrac{k_{100^{\circ}C}}{k_{90^{\circ}C}}$?

How should I approach this problem? I have no idea what to do here, though it seems like an interesting problem.The given answer is 

>!100