Final answer:
The original question is ambiguous, as it could relate to either principles of electricity in physics or economic calculations involving rent values, and requires further clarification for an accurate response.
Step-by-step explanation:
The question appears to involve calculating current values at various points (labeled A, B, C, and D) and may relate to the principles of electricity and circuitry which is part of physics. However, there's a possibility that the question could be misinterpreted due to the mention of rent values, which could imply a real-world scenario involving finance or economics. The reference to Chapter 5 and calculations of Price Elasticity of Demand further suggests that the subject could be Economics. Since the question isn't clear in its context and specifics, it is recommended to ask the student for clarification. Without additional information, providing an accurate answer is not possible.