Ans: $20\%$

$\text{P}\left(1+\dfrac{\text{R}}{100}\right)^2=1.44\text{P}\\\Rightarrow \left(1+\dfrac{\text{R}}{100}\right)^2=1.44\\\Rightarrow 1+\dfrac{\text{R}}{100}=1.2\\\Rightarrow \dfrac{\text{R}}{100}=0.2\\\Rightarrow \text{R}=20$