For (ii), please remember the formula for volume of a hemisphere by heart. For the cylindrical container, volume of water inside has changed and because base circular area has not changed, only height of water will change. Use the same method as the (i) to do.

For (iii), please remember that mililitre and centimetre cube are convertible, convert all the quantities to the same unit and just divide the total volume of water by the rate of water flow out to find the time.