天山-6-19,25好像没有讨论过 - ChaseDream

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 $4080,what is the value of X?

(2) the ration 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 photograher will arrange 6 people of different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row. The heights of the people within each row must increase from left to rigth,and each person in the second row must be taller than the person standing in front of him or her. how many such arrangements of the 6 people are possible?

以下是引用vineyard在2005-3-8 7:42:00的发言：

Q19:

(1) X=(3/4)Y

(2) the ration 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.

ANS:C

A+B=60000, X%A+X%B=4080

(2)A/B=3/2, A=36000,B=24000, (1)X%36000+(4/3)X%24000=4080

Q25:

A.5 B.6 C.9 D.24 E.36

ANS:A

123 124 125 134 135

456 356 346 256 246

how to get these two answers?

Thank you!!

以下是引用beautywawa在2005-3-8 8:29:00的发言：
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我觉得but(...)of this amout earned simple annual interest at the rate of x percent per year...