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PS - Candy bar

by Xbond » Fri Sep 11, 2009 10:58 am
Hi there,

Could you give me your ELEGANT, QUICK, and EFFICIENT method to resolve (with these concepts and with finding the solution).


A certain candy manufacturer reduced the weight of Candy Bar M by 20 percent but left the price
unchanged. What was the resulting percent increase in the price per ounce of Candy Bar M?

a)5%
b)10%
c)15%
d)20%
e)25%
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by g1988enator » Fri Sep 11, 2009 11:46 am
u can solve this by unitary method like
if 100 ou are for 100 then 80 will be for 80 but he is selling thm for 100
so profit is of 20 and c.p is 80 so profit will be 25 %
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by truplayer256 » Sat Sep 12, 2009 1:34 pm
Candy Bar M weighs x ounces and costs y dollars. The cost per ounce is y/x.

Since the candy manufacturer reduced the weight of Candy Bar M by 20% but left the price unchanged, the cost per ounce would be 5y/4x, a 25% increase from the former price per ounce of Candy Bar M.
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by Xbond » Mon Sep 14, 2009 12:49 am
many thks

OA is E
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hi

by Scott@TargetTestPrep » Tue Dec 12, 2017 7:18 am
A certain candy manufacturer reduced the weight of Candy Bar M by 20 percent but left the price
unchanged. What was the resulting percent increase in the price per ounce of Candy Bar M?

a)5%
b)10%
c)15%
d)20%
e)25%
We are given that a certain candy manufacturer reduced the weight of Candy Bar M by 20 percent but left the price unchanged. If we let w = the original weight of the bar, the new weight is 0.8w = 4w/5. If we let p = the original price of the bar we know:

p/w = the original price per ounce of the bar

p/(4w/5) = 5p/4w = the new price per ounce of the bar

Finally we can determine the resulting percent increase in the price per bar due to the change:

[5p/4w - p/w]/[p/w] x 100

[5p/4w - 4p/4w]/[p/w] x 100

[p/4w]/[p/w] x 100

p/4w x w/p x 100 = 1/4 x 100 = 25%

Answer: E

Alternate Solution:

Rather than use letters, we can use convenient numbers to answer the question.

Let's let the original price of the candy be $20, with a weight of 10 ounces. Thus, the original price per ounce is 20/10 = $2.00 per ounce.

The new bar has the same price of $20, but the weight has been reduced by 20%, making the new weight 10 x 0.8 = 8 ounces. Now, the new price per ounce is 20/8 = $2.50 per ounce.

We use the percent change formula, which is (New price - Old price)/Old price x 100%. We obtain:

(2.50 - 2.00)/2.00 x 100%

.5/2 x 100% = 5/20 x 100% = 25%

Scott Woodbury-Stewart
Founder and CEO
[email protected]

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