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匿名 發問於 科學及數學數學 · 6 年前

maths question

1. mr mok deposits a sum of money in a bank at 5又1分之2% p.a. Find the sum of money that mr mok deposits if he can get $2310 as simple interest after 3 years.

solution Let x be the sum of money.

2. flora borrows $36000 from a finance company at 3.75% p.a. simple interest. if

she has to return a total amount of $45450, how long does she borrow?

3. a cat and a dog are not satisfied with their weights. if the weight of the cay is increased by 20% while that of the dog is decreased by 10% , their weights will be the same. what percentage of the dog's original weight is the cat's original weight?

1 個解答

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  • 6 年前
    最愛解答

    1

    x(1+5.5% x 3) = 2310

    x = 2310/1.165 = 1982.83

    2

    36000 (1 + 3.75%x) = 45450

    3.75%x = 1.625 - 1

    x = 0.625/3.75% = 16.67yrs

    3

    x + 20%x = y - 10%y

    y (1-10%) = x (1 + 20%)

    y/x = 0.9/1.2 = 75%

    2014-08-18 16:47:15 補充:

    Q3

    應是 y/x = 1.2/0.9 = 133.33%

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