Water in Tank A:
Volume = 1.5 × 1.0 × 0.60 = 0.9 m³

Water already in Tank B:
Volume = 1.2 × 0.75 × 0.10 = 0.09 m³

Total water in Tank B after pouring = 0.9 + 0.09 = 0.99 m³

Base area of Tank B = 1.2 × 0.75 = 0.9 m²

Final depth = 0.99 ÷ 0.9 = 1.1 m

Final Answer: 1.1 m