Let the amount invested at 6% be $x then the rest is $27000-x.
Interest on $x is 0.06x and interest on $27000-x is 0.05(27000-x).
Total interest is 0.06x+0.05(27000-x)=1530.
0.06x+1350-0.05x=1530, 0.01x=1530-1350=180, so x=180/0.01=$18000 and $27000-18000=$9000.
So $18000 at 6% and $9000 at 5%.