Calculate the $\frac{P}{E}$ ratio

Baxter has a retention ratio of $63\%,$ a ROE of $15\%,$ and a discount rate of $12\%.$ What is its $\frac{P}{E}$ ratio $($assuming the market correctly values the company$)?$

Hint: Remember the earlier class material $($also on slide $43$ ROE $*$ retention $=$ growth. Not that this says what the retention ratio is$...$ do you need the retention ratio or something else that can be calculated knowing the retention ratio in the numerator of the $\frac{P}{E}$ equation?

Note: Enter your answer with two decimals.