Problem: Mr. A owns a home worth $10,000. He sells it to Mr. B at a 10% profit. Mr. B sells the house back to Mr. A at a 10% loss. Then:
Answer Choices:
A. A comes out even
B. A makes $100 on the deal
C. A makes $1000 on the deal
D. A loses $100 on the deal
E. A loses $1000 on the deal
Solution:
S1​=10,000+1000=11,000,S2​=11,000−1100=9900, S1​−S2​=1100.∴(B) is the correct choice.