请教几个模考数学题目 谢谢

Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?
(1)    Two of the interior angles of ABCD are right angles.
(2)     The degree measure of angle ABC is twice the degree measure of angle BCD.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
为什么答案选c呢？ 我觉得应该是E~~ 请教。。。谢谢

PREP 2里面又说是E，因为可能有45.，90

Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?
(1)    Two of the interior angles of ABCD are right angles.
(2)     The degree measure of angle ABC is twice the degree measure of angle BCD.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
为什么答案选c呢？ 我觉得应该是E~~ 请教。。。谢谢


Q10:
$10,000 is deposited in acertain account that pays r percent annual interest compounded annually, theamount D(t), in dollars, that the deposit will grow to in t years is given byD(t) = 10,000 {1+(r/100)}^t. What amount will the deposit grow to in 3 years?
(1) D(t) = 11,000
(2)            r =10

A. Statement (1) ALONEis sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONEis sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHERare sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONEis sufficient.
E. Statements (1) and (2) TOGETHERare NOT sufficient.
答案是D 为什么1）也是sufficient的？ 不理解。。。