percentage and Interest

2009-01-28 3:37 am

1.The weight of Mary is 20% more than Tim.It is given that Cindy
weight 60kg.
(a) Find the weight of Tim.
(b) The weight of Susan is 20%less than that of Mary.Are Susan
and Tim of the same weight?Explain.

2.The cost of a calculator is $160.If calculator is sold at its marked
price ,then the percentage profit is 25%.
(A)find the marked price of the calculator
(b)If the calculatoris sold at a 10% discount on the marked price,find
the percentage profit or percentage loss.

3.A sum of $5000 is deposited at 2% p.a. for 3year,compounded
yearly .Find the interest correct to the nearest dollar.

幫幫忙!

回答 (1)

myisland8132

2009-01-28 3:50 am

✔ 最佳答案

1The weight of Mary should be 60 kg
So the weight of Tim is 60/(1+20%)=50 kg
(b)
Let the weight of Susan is x
The weight of Susan is 20% less than that of Mary
(60-x)/x=0.2
60-x=0.2x
60=1.2x
x=50
Susan and Tim are of the same weight.
2
(a) marked price of the calculator
=160*(1+25%)
=200
(b)
New price
=200*(1-10%)
=180
So
the percentage profit
=(180-160)/160*100%
=12.5%
3
Accumulated value
=5000*(1+2%)^3
=5306.04
the interest
=5306.04-5000
=306 (correct to the nearest dollar)

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