Problem: The price of an article was increased p%. Later the new price was decreased p%. If the last price was one dollar, the original price was:
Answer Choices:
A. 2001−p2
B. 1001−p2
C. one dollar
D. 1−10,000−p2p2
E. 10,000−p210,000
Solution:
Let the original price be P. Then P1=(1+100p)P.
P2=(1−100p)P1=(1−100p)(1+100p)P=1;∴P=1−(p2/1002)1=10,000−p210,000.