A hypothetical open economy has a marginal propensity to import $($mpi$)$ equal to $0\mathrm{.}2$ and a marginal propensity to consume ewual to $0\mathrm{.}7.$ assume that the economy is initially in equilibrium. Reger to scenario $10\mathrm{.}2.$ What is the marginal propemsity to save of this economy