涛涛数学 几道题求解

freebird1984

Q10:

$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.

答案D  （1）为什么对

Q17:

Box W and Box V each contain several blue sticks and red sticks, and all of the red sticks have the same length.  The length of each red stick is 18 inches less than the average length of the sticks in Box W and 6 inches greater than the average length of the sticks in Box V.  What is the average (arithmetic mean) length, in inches, of the sticks in Box W minus the average length, in inches, of the sticks in Box V?



A.    3

B.    6

C.    12

D.    18

E.    24

答案E

freebird1984

自己顶一下，为啥数学就没有人答疑呢

solosky1005

第一题好像有人补充过的，D（t）中的t是一个已知数字，好像是1
第二题设红色的长度为x，那么W是x+18,V是x-6，那么两者相差的长度只要相减一下好了，就是24