 In this page:
Worked Example 2
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In this example, I will use the
following strategies: (1) Make a Supposition
(2) Use an Equation
(3) Use Ratio
Worked Example 2
Mr. Lim bought an antique vase from a shop. The shop sold it
to him at a profit of 15%. After 3 years, Mr. Lim sold the vase to Mr. Koh at 25% loss.
After another 7 years, Mr. Koh sold the vase to Miss Chong at 20% profit. Is Miss Chong
paying more or less than or the same as the cost price of the vase? Is Miss Chong buying
it cheaper than Mr. Lim did?
Suppose the cost price of the antique vase is $100.
Shop sold to Lim, it is sold
at = 115% x $100 = $115
Lim
sold to Koh, it is sold at = 75% x $115 = $86.25
Koh sold to
Chong, it is sold at 120% x $86.25 = $103.50
$103.50> $100 Thus, Miss Chong paid more than the cost
price.
$103.50< $115 Thus, Miss Chong paid less than Mr. Lim.
Let the cost price of the vase = $y
Shop sold to Lim, it is sold at = 115% x $y = $1.15y
Lim sold to Koh, it is sold at = 75% x $1.15y = $0.8625y
Koh sold to Chong, it is sold at 120% x $0.8625y
= $1.035y
$1.035y > $y Thus, Miss Chong paid more than the cost
price.
$1.035y < $1.15y Thus, Miss Chong paid less than Mr. Lim.
Shop : Lim = 100 : 115
Lim : Koh = 115 : 86.25
Koh : Chong = 86.25 : 103.5
103.5> 100 Thus, Miss Chong paid more than the cost
price.
103.50< 115 Thus, Miss Chong paid less than Mr. Lim.
Let's proceed to Example 3. |
