Answer to Question #330900 in Algebra for Shang

Question

4.Three women bought notebooks which was advertised to be P27.00 each. Each give P10.00 to the agent, and ask her to bring back P3.00. The agent returns to the desk. where she learns that the notebook is actually only P25.00 each. She gives P25.00 to the desk clerk, returns to the women, and gives back each P1.00, deciding not to tell them about the actual rate. Thus the agent has pocketed P2.00, while each guest has spent 10-1-P9, a total of 2+3-9-P29. What happened to the other peso?

Answer 1

It is incorrect to sum the amount pocketed by the agent with the sum given by three women because these women spent their money but the agent gained (not spent) P2.00. If we look at system of women + agent then we should calculate balance like this: $-3\cdot9+2=-25$ , so we can see that this system lost P25.00, that is the cost of the book.