急！中一英文數學題?

In the figure, a swimming pool in the shape of a right prism is 25 m long and 18 m wide. The depth of water is 5 m at the deep end and 3 m at the shallow end. The distance bue between the pool edge and the water surface is 0.3 m. 
(a) Find the volume of water in the pool. (b) If half of the water in the pool is drained away, what is the distance between the pool edge and the water surface?

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