Let the amount invested with 5% interest be x
Therefore, the amount invested with 6% interest will be (6000-x)
It is given that the total interest earned yearly is $337.5. Thus, the equation of interest will be:

Multiplying both sides by 100 we get:


Subtracting both sides by 36000 we get:


Thus, the amount invested at 5% is $2250
Therefore, the amount invested at 6% will be $(6000-2250)=$3750