Home › CMA Foundation › businessmathematics › Proportions › The four quantities a, b, c, d are in proportion…
The four quantities a, b, c, d are in proportion if:
Aa + d = b + c
Bab = cd
Cac = bd
Dad = bc
Answer & Solution
Correct answer: D. ad = bc
1. Per OCR: "The four quantities a, b, c, d are in proportion if a/b = c/d, or ad = bc."
2. Cross-multiplication rule.
3. Converse also true.
_Source: ICMAI BoS CMA Foundation Paper 3 (FBMS) — Paper3_07042026.pdf, Module 1 §1.1 (page 12)_