请教PREP-DS1-197解题思路***急***

wj37044 · 发表于 2009-4-4 21:22:00

197. 19209-!-item-!-187;#058&012193

Jason's salary and Karen's salary were each p percent greater in 1998 than in 1995. What is the value of p ?

(1) In 1995 Karen's salary was $2,000 greater than Jason's.

(2) In 1998 Karen's salary was $2,440 greater than Jason's.

key:c

我设:

1995 1998

Karen: x+2000 y+2440

jason: x y

C 只能的出karen 比jason 的增长多440(440+Y-x-y+x),但求不出各自增长的百分比呀? 请提供思路

ezailshi · 发表于 2009-4-4 21:57:00

y=x(1+p); y+2440=(x+2000)(1+p)

y/x=y+2440/(x+2000) --> xy+2440x=xy+2000y --> y/x=2440/2000 --> 1+p=2440/2000

vivien_hu · 发表于 2009-4-4 22:02:00

1995 1998

J X X（1+P）

K X+2000 (X+2000)(1+P)

(X+2000)(1+P)=X(1+P)+2440

得P

DorothyWRSC · 发表于 2009-4-4 22:13:00

ls的解释得很好了。选C

请教PREP-DS1-197解题思路急