$220$ points

A first stage solid rocket has the following characteristics:

Sea$-$Level Thrust is $202,201lb{b}_f$

Mass flow rate is $804\mathrm{.}9lb\frac{m}{s}$

Nozzle Exit Pressure is $8\mathrm{.}7$ psi

Throat area is $170\mathrm{.}0i{n}^2$

Area ratio is $10\mathrm{.}9$

Find: The specific impulse at sea level, $s$