IAS 21 Effects of changes in foreign exchange rates

Hello opentuition,
Some clarification on the question of ROSE under consolidation foreign operations in that BPP Revision Kit.

The parent co ROSE acquired 70% in petal and later an additional of 10%.
Meaning the ROSE now holds 80% and NCI being 20% from 30%.

In the solution when computing the group share in post acquisition profits they use 70% instead of 80% and NCI 30% instead of 20%. Any logic here???? Some help. Thx