GWD-13-14(DS)

[kikisky]

對不起~我不知道要貼題目XD
如下
請各位大大幫忙囉

$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



這題答案是(D)
請問~為什麼條件(1)單獨狀況下可成立??
D(t)並沒有說明t的值
t可等於1或3或任意數不是嗎?(因為r也是未知數啊~)
所以~D(t)=11,000可以是3年的錢或是任意數的年份的$$啊~

[kikisky]

對不起~我不知道要貼題目XD
如下
請各位大大幫忙囉

$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

[huacy]

可否把所有選項列出?

[Behemoth]

選項就是1.2而已阿

這題是ds...:)

[魚]

hi kiki :

my reasons as follow :

the question ask you that: "What amount will the deposit grow to in 3 years? " & condition (1)D(t) = 11,000 " . 1,1000 is a constant. it means : no matter what " t " or "r" is , the result of D(t) is the same :D

[kikisky]

啊~是這樣啊??
怎麼我今天第一次才知道有這種用法??(程度太差@ @)

[Grace]

Hello Fish,
Sorry, I still do not quite get what you mean.
My solution for this question is as follows (kindly check if there is any wrong concept.)

==>11000=10,000 {1+(r/100)}^3 t代入3可求出R so we can get the amount that the deposit will grow in 3 years-----Am I wrong?


Help~ :D

[homaru]

題目問What amount will the deposit grow to in 3 years?
問的就是D(t)=?
而第一條件就直接點出答案11000
第二條件D(t) = 10,000 {1+(10/100)}^3=13310

[Grace]

ETS有這麼好心 給個條件1這麼簡單易選的條件嗎??
真的有點懷疑..考出來還真不知該不該選??

總之 謝謝homaru 的解答...

[liwuu]

題目問What amount will the deposit grow to in 3 years?
問的就是D(t)=?
而第一條件就直接點出答案11000
第二條件D(t) = 10,000 {1+(10/100)}^3=13310

雖然我對以上大大的解釋同意,但是我對這一題很存疑
因為
(1)依照ETS出題,應該不至於出現分別依條件一和條件二所算出的答案不同
(2)由條件一,乍看起來就是不論你投資多少年,反正就是11000...這超怪的!!
若是他用D(x)=11000,就不會那麼奇怪了!!(x為一特定未知年數)
如果考試出現上述條件,那麼答案就是B了吧!!

[jfan]

我也來問一下這題的第一個條件

條件一可知： D(t)=11,000=10,000(1+r%)^t 有兩個未知數 r 與 t。直覺可判斷 r=10, t=1 滿足此式，但這樣決定第一個條件滿足，是否有些武斷，會不會有其他的 r,t 組合也滿足呢。若沒有一個很明確的解法，會不會選 B 比較穩健？

[JS]

我也來問一下這題的第一個條件

條件一可知： D(t)=11,000=10,000(1+r%)^t 有兩個未知數 r 與 t。直覺可判斷 r=10, t=1 滿足此式，但這樣決定第一個條件滿足，是否有些武斷，會不會有其他的 r,t 組合也滿足呢。若沒有一個很明確的解法，會不會選 B 比較穩健？

statement 1 D(t) = 10000(1+r%)^3=11000
statement 2 D(t) = 10000(1+10%)^3=13310

If the answer is D one of the figures in Statement 1 and 2 must be wrong.

[puresillylily]

Could it be possible there is a typo in this question stem itself ?
If the question were stated as the following, the answer D would work perfectly.
(1) D(1) = 11,000
(2) r= 10
Condition (1) D(1) = 11,000 ==> r=10
D(t) = 10,000 {1+(r/100)}^t =10,000 {1+(10/100)}^t
D(3) = 10,000*1.1^3
Condition (2) D(t) =10,000{1+(10/100)}^t

Answer: D { only if (1) D(1)=11,000}

[chris8888]

yeah, probably what puresillylily tried to tell us is right.

And that'll make sense.