How does it solve to C

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How does it solve to C

by tanyajoseph » Fri Aug 24, 2007 12:07 am
During a two week period, the price of an ounce of silver increased by 25 percent by the end of the first week and then decreased by 20 percent of this new price by the end of the second week. If the price of silver was x dollars per ounce at the beginning of the two week period, what was the price, in dollars per ounce, by the end of the period?

A) 0.8x
B) 0.95x
C) x
D) 1.05x
E) 1.25x
Source: — Problem Solving |

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by agps » Fri Aug 24, 2007 1:02 am
assume x to be 100 (always a good choice when working with percentages)

at the end of the first week the value increased 25%
100 + 25 = 125

at the end of the second it decreased 20%
(20% 0f 125 is 25)
125 - 25 = 100

so the value at the end was the same than at the beginning, or x

C is the answer