求教OG里的一道data sufficiency

sunnycl

OG quantitative 第一版中的data sufficiency中第十题不懂
of the 230 single-family homes built in city X last year, how many were ovvuoied at the end of the year?
(1)of all single-family homes in city X, 90 percent were occupied at the end of last year
(2)a total of 7200 single-family homes in city X were occupied at the end of last year
答案是E statements 1 and 2 together are not sufficient.
为什么2也是not sufficient啊？
请教！！！谢谢！

crazyxxx

貌似是不知道在230个里包括了多少吧,只知道所有single + occupied

sunnycl

谢谢，但是还是不是很懂，问题不是occupied吗，2不是已经回答了有7200吗