Problem: A house worth $9000 is sold by Mr. A to Mr. B at a 10% loss. Mr. B sells it to Mr. C at a 10% profit. Mr. C then sells it to Mr. D at a 10% loss. Mr. D sells it back to Mr. A at a 10% profit. The price paid by Mr. A for the house is
Answer Choices:
A. Mr. A breaks even
B. Mr. B gains $900
C. Mr. A loses $900
D. Mr. A loses $810
E. Mr. B gains $1710
Solution:
B pays A 9000−101​⋅9000=$8100.
A pays B 8100+101​⋅8100=$8910.
Thus A has lost 8910−8100=$810.