Let x be the amount invested in 3% interest so that 10000−x is the amount invested in 1.2% interest.

The interest earned is $215.04 so we can write:

0.03(x)+0.012(10000−x)=215.04

Solve for x:

0.03x+120−0.012x=215.04

0.018x+120=215.04

0.018x=95.04

x=5280

So, you invested $5280 at 3% and $10000 - $5280 = $4720 at 1.2%.

The interest earned is $215.04 so we can write:

0.03(x)+0.012(10000−x)=215.04

Solve for x:

0.03x+120−0.012x=215.04

0.018x+120=215.04

0.018x=95.04

x=5280

So, you invested $5280 at 3% and $10000 - $5280 = $4720 at 1.2%.