Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?
(1) She bought $4.40 worth ofstamps.
(2) She bought an equal numberof $0.15 stamps and $0.29 stamps.
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 NOTsufficient.
题目全解：第一个条件可写出等式：4.4=0.15x+0.29y 则有 44=1.5x+2.9y
DS：What is the value of|x| ?
(2) x^2 = 4