英语翻译Carol subscribed to four publications that cost $12.90,$16.00,$18.00,and $21.90 per year,respectively.If she made an initial down payment of one half of the total amount,and paid the rest in 4 equal monthly payments,how much was the each of the four monthly payments?

问题描述:

英语翻译
Carol subscribed to four publications that cost $12.90,$16.00,$18.00,and $21.90 per year,respectively.If she made an initial down payment of one half of the total amount,and paid the rest in 4 equal monthly payments,how much was the each of the four monthly payments?

Carol (人名)订了四份杂志,年定价分别是$12.90,$16.00,$18.00,和$21.90.她首期付款了总价的一半,余款在4个月内平均支付,则这4个月每月需支付多少美元