Amount of investment needed to increase the economy by a particular percentage is

The investment required is $\mathrm{ICOR}\times\Delta Y$. The incremental capital-output ratio is $\mathrm{ICOR}$ $=\Delta K/\Delta Y$, and investment adds to the capital stock, so the required capital addition is $\Delta K$ $=\mathrm{ICOR}\times\Delta Y$. Here $\Delta Y$ is the increase in output.