[計量] GWD一題數學

看板GMAT作者 (allen)時間13年前 (2011/08/05 22:15), 編輯推噓3(3010)
留言13則, 3人參與, 最新討論串1/2 (看更多)
A total of $60,000 was invested for one year. Part 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 =3/4x (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. 這題答案是C 但我選E 兩部份投資的錢都不知道 只知道X和Y的關係怎麼湊得出X是多少? 假設第一部份投資A (1+x%)A+(1+y%)(60,000-A)=4080 根據1或2或1和2都沒辦法求出X吧? 這題寫過兩次 第一次以為答案錯 第二次又出現 所以有點懷疑 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.40.160.177

08/05 22:22, , 1F
btw 我寫的是GWD數學30套的 好像常常答案有誤 有人有
08/05 22:22, 1F

08/05 22:22, , 2F
比較正確或更新過的答案嗎? 謝囉
08/05 22:22, 2F

08/05 22:56, , 3F
你第一個條件應該寫錯了 然後我覺得答案是C
08/05 22:56, 3F

08/05 22:56, , 4F
想知道打電話給我
08/05 22:56, 4F

08/06 10:45, , 5F
條件一手殘 X=3/4Y
08/06 10:45, 5F

08/06 11:02, , 6F
兩個合併解的出來
08/06 11:02, 6F

08/06 11:02, , 7F
兩部份分別是 40,000 跟 20,000
08/06 11:02, 7F

08/06 11:03, , 8F
然後 interest rate 第一個 x 是 0.0612, 第二個 y 是0.0816
08/06 11:03, 8F

08/06 11:05, , 9F
第二個條件單獨可以知道第一跟第二部份賺的利息是多少
08/06 11:05, 9F

08/06 11:06, , 10F
第一條件單獨可以知道兩利率 x,y 之間的關係, 把其中一個替
08/06 11:06, 10F

08/06 11:06, , 11F
換成同一單位後就可以結合出必要元素求出來數字
08/06 11:06, 11F

08/06 11:09, , 12F
喔還有, 依照你的公式最後應該是等於 64080, 不是 4080
08/06 11:09, 12F

08/06 11:17, , 13F
感謝回答!
08/06 11:17, 13F
文章代碼(AID): #1EE_i3HO (GMAT)
討論串 (同標題文章)
文章代碼(AID): #1EE_i3HO (GMAT)