First calculate the present value of the five 3 000$ payments,

PV1 = 3000*[(1-(1,06)^(-5))/0,06] = 12 637.09$

Then use the increasing annuity formula for the increasing 500$,

PV2 = 500*[[(1-(1,06)^(-5))/0,06]*1,06-5*(1,06)^(-5)]/0,06 = 6073.46$

Add the the annuity,

PV1+PV2= 18 710.55$