Question: I hold 100 shares bought at ₹250 each. The company announces a rights issue in a 1:4 ratio (1 new share for every 4 held) at an issue price of ₹150 per share, and I subscribe to my full entitlement. What is my effective average cost per share across my entire holding after the rights issue?
Answer: Effective average cost per share ≈ ₹230.

Supporting evidence:
title: Inline formula / method note
quote: Standard cost-basis computation for rights issue subscription — basic securities-holding mathematics
context: Standard cost-basis computation for rights issue subscription — basic securities-holding mathematics.