問一題PP的DS，請大大幫忙

To fill an order on schedule, a manufacturer had to produce 1,000 tools per day for n days.  What is the value of n ?

(1) Because of production problems, the manufacturer produced only 600 tools per day during the first 5 days.

(2) Because of production problems, the manufacturer had to produce 1,500 tools per day on each of the last 4 days in order to meet the schedule.

答案是E

不是C就可以解出N=9了嗎？

難道還有其他解？