OC-voltage-gain for cascaded amplifier
The question is poorly worded, and of the two possible ways to connect the amplifiers I think you picked the one that is different from what the instructor assumed.

I think the question intends that the output of the amplifier with \$R_O = 10\,\text{k}\Omega\$ is connected to the input of the amplifier with \$R_i = 10\,\text{k}\Omega\$. And that's a big hint right there...