jmc

For the first six months, the (simple) interest rate is $12/2=6$ percent. Therefore, the investment grows to $10000\cdot 1.06=10600$.

Let the annual interest rate of the second certificate be $r$ percent. Then the interest rate for six months is $r/2$, so the investment grows to $10600\cdot \left(1+\frac{r/2}{100}\right)$. Therefore, $$10600\cdot \left(1+\frac{r/2}{100}\right)=11130.$$ Then $$1+\frac{r/2}{100}=\frac{11130}{10600}=1.05,$$ so $r/200=0.05$, which means $r=\boxed{10}$.