Step 1

Total volume of water present = 31 x 29 x 30 = 26970

Step 2

When divider is removed, 26970 cm3 of water will fill the rest of the container, hence

26970 = base area x height

26970 = (60 x 30) x height

height = 14.983 = 15.0 (to 1 decimal place)

Hope that helps!

Enso Education