revenue with equations

please sir help me The following information relates to questions 24 and 25: A company has established the following selling price, costs and revenue equations for one of its products: Selling price (£ per unit) = 50 – 0·025Q Marginal revenue (£ per unit) = 50 – 0·05Q Total costs per month (£) = 2,000 + 15Q Q represents the number of units produced and sold per month. 24 At what selling price will monthly profits be maximised? A £15·00 B £17·50 C £25·00 D £32·50 25 What would be the monthly profit if the selling price per unit was set at £20? A £1,000 B £4,000 C £6,000 D £12,000