Maths`(Simple Interest)10 FUN>

用戶53180

2008-02-29 1:34 am

Plz Show me the steps also, thx*=)

1)Wendy has a deposit in a bank. If the simple interest rate is increased from 8%p.a. to 9.5% p.a. , she will get an additional of $62.5 every month. Find the deposit.

2) Jeffrey borrows $75000 from a finance company at 12% p.a. simple interest rate. He must pay back the amount within 30 days. If the payment is overdue, the interest after 30days will be calculated at a simple interest rate of 20% p.a. How much will he need to pay if he pays back the amount 40 days after borrowing? Give the answer correct to the nearest dollar. (Take 1 year = 365 days. )

回答 (1)

數學神算子

2008-02-29 1:47 am

✔ 最佳答案

1)Let x be the deposit
x(9.5%)(1/12)-x(8%)(1/12)=62.5
x=50000

2008-02-28 17:52:58 補充：
The amount of 30 days:
75000x12%x30/365
=54000/73
the amount of 40 days
54000/73(20%)(10/365)+54000/73
=$744

2008-02-28 17:58:23 補充：
sorry，我上面個補充錯左
應該係：
the amount of the first 30 days：
75000(1+(12%/265))^30
=$75743.26
The amount at the last 10 days
75743.26x(1+(20%/365))^10
=$76159(to the nearest dollars)

2008-02-28 17:59:48 補充：
真係唔好意思，開頭第一個補充教錯左你，
第二個就應該岩架喇，
如果仲有唔明，可以問我
如有錯誤，請多多指教^^
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