求一道GMAT数学题.

求一道GMAT数学题.
At a certain bookstore,the regular price of each book is 20 percent less than its list price.If during a sale the price of each book at the store was 15 percent less than its regular price,then the price of a book during the sale was what percent less than its list price?
A.30%
B.32%
C.35%
D.38%
E.40%
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.
$10,000 is deposited in a certain account that pays r percent annual interest compounded annually,the amount D(t),in dollars,that the deposit will grow to in t years is given by D(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) 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.

1) 1-80%*85%=32% B
2) C 由于问题是一般疑问句
3）E 由于问题是特殊疑问句