Explain steps please

Afnan has the opportunity to buy a time share in Florida, if she can save enough for the down payment. She has calculated that if she deposits $6,475.00 today, $7,119.00 in 4 weeks, and $4,540.00 in 17 weeks in an account earning i(12)=2.540%, then at the end of 23 weeks she will have exactly enough. How much is the down payment? a. $16,640.89 b. $17,189.49 c. $18,286.69 d. $17,738.09 e. $17,372.36 Your answer is incorrect. The correct answer is: $18,286.69