If a < y < z < b, is |y - a| < |y - b| ?
(1) |z - a| < |z - b|
(2) |y - a| < |z - b|
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
感觉是不是不用那两个条件,单靠 a < y < z < b,题目问的不等式就能成立了?
看到绝对值就画图,其实就是比较两点间距离的大小。不用太纠结每个数具体的值
画个图,把a,y,z,b看成一条线上的四个点,按照从小到大向右排列
1)|z - a | < |z - b |说明za之间的距离比ab之间的距离小,y在z的左边,那么ya之间的距离比yb之间的距离更小,能推出|y - a | < |y - b |
2)|y - a | < |z - b | yb之间的距离大于zb,所以 |y - a | < |y - b |
不要想得太复杂了
画数轴就很简单。
y