Percentages

用戶217087

2008-07-31 2:16 am

A cat and a dog are not satisfied withtheir weights.
If the weight of the cat is increase by 20% while that of
the dog is decreased by 10%, their weights will be the same. what
What percentages of dog's original weight is cat's original
weight?

Flora borrows $36 000 from a finance company at 3.75% p.
a. simple interest. If she has to return a total amount of
$45 450, how long does she borrow?

回答 (1)

waiting

2008-07-31 3:25 am

✔ 最佳答案

Let’s the cat's original weight be a, the dog's original weight be b,a(1+20%) = b (1-10%)a(1+20%) /b = (1-10%)a /b= (1-10%)/(1+20%)Thepercentages of dog's original weight is cat's original weight:[(1-10%)/(1+20%)]X 100%=90/100 X 100/120 X 100%=3/4X 100%=75%Total amount = principal + principal X interest rate X period = principal X (1+interest rate X period)Totalamount = principal X ( 1+interest rate X period)Letshe borrows for tyears,45450= 36000 x ( 1+ 3.75%Xt)1.2625=1+tX3.75%0.2625=375t/100002625=375tt=7Sheborrows for 7 years.

參考: myself

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