Suggested answer:

8000cm³ / 1600 cm² = 5cm

a) Height of water in Tank Y at first is 5 cm.

1400 cm² x 8 cm = 11200 cm³

11200 cm³ + 8000 cm³ = 19200 cm³

1600 cm² + 1400 cm² = 3000 cm²

19200 cm³ / 3000 cm² = 6.4 cm

b) New water height is 6.4 cm

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