I'm having trouble with question#26, Jack won a sweepstake jackpot, payable in form of a 15 year annuity with equal annual payments beginning immediately and totaling $300000. If he wishes, he can choose to instead receive the present value of his annuity, calculated by using a 7.5% interest rate. How much would he get under that option?

I don't understand how the answer equals $1897830.75