You are making forecasts for two securities that promise perpetual, growing annual cash flows. For both securities$,$ calculate the cash flow you can expect at the end of year $7($that is$,$ seven years from now$).$ a$.$ Security A will pay $$10$ next year $($year $1),$ and the cash flows will grow at a rate of $2\%$ per year thereafter.

b$.$ Security B paid $$9$ last night, and the cash flows are expected to grow at a rate of $2\mathrm{.}5\%$ per year.

please explain.