ChaseDream

标题: 求助GWD一道数学题，谢谢！ [打印本页]

作者: wuyan830308 时间: 2008-12-5 13:44
标题: 求助GWD一道数学题，谢谢！

1、A total of $60,000 was invested for one year. But of this amount earned simple annual interest at the rate of x percent per year, and the rest earned simple annual interest at the rate of y percent per year. If the total interest earned by the $60,000 for that year was $4,080, what is the value of x?

(1) x = (3/4) y

(2) The ratio of the amount that earned interest at the rate of x percent per year to the amount that earned interest at the rate of y percent per year was 3 to 2.

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.

Answer: (C)

2、If n = 8¹¹ – 8, what is the units digit of n?

A. 0

B. 1

C. 4

D. 6

E. 8

Answer: (C)

数学不大好，数还没大数明白，见笑了。不过上面的题的确没大明白！

作者: wuyan830308 时间: 2008-12-6 04:50
who can help me to answer the questions? quite thanks!

作者: yeefay 时间: 2008-12-6 21:05

第一个,设获利x的部分本金为A, 则获利y的部分本金为600,000-A

列方程A*X +(600,000-A)*Y=4080

这是个三元方程,通常需要三个方程组成方程组才有解.所以1,2同时都得用上.答案是C

第二个,8N次方后个位依次是8,4,2,6的循环,则11次方后为2,

2-8借一位就是12-8=4

作者: gyyygyyy 时间: 2008-12-6 21:10
楼上正解

欢迎光临 ChaseDream (https://forum.chasedream.com/)