Parameter ratio from a linear relation: If 1.5 * a = 0.04 * b, find the value of (b − a) / (b + a).

Introduction / Context:
This question tests using a given proportional relation between two variables to compute a derived ratio. Recognizing and simplifying ratios prevents unnecessary algebra.

Given Data / Assumptions:

• Relation: 1.5 * a = 0.04 * b.
• We need (b − a) / (b + a).

Concept / Approach:
Compute r = b/a from the given equation, then express the required ratio in terms of r only: (b − a)/(b + a) = (r − 1)/(r + 1).

Step-by-Step Solution:

Verification / Alternative check:
Pick a convenient a (e.g., a = 2). Then b = 37.5 * 2 = 75. Compute (75 − 2)/(75 + 2) = 73/77, confirming the general result.

Why Other Options Are Wrong:
36/38 is a rounded version (reduces to 18/19) and not exact. 77/73, 73/70, and 73/75 invert or perturb the ratio and do not satisfy the derived expression.

Common Pitfalls:
Computing b/a incorrectly (e.g., inverting 1.5/0.04), or forgetting to transform (r − 1)/(r + 1) exactly, leading to rounding errors.

Final Answer:
73/77