The bangor coat factory found that the number of coats sold n varies directly as their advertising budget a and inversely as the price of each coat p. the bangor coat factory sold 10,800 coats when $30,000 was spent on advertising and the price of a coat was set at $50. determine the number of coats sold when the amount spent on advertising is increased to $70,000

a) 3888 coats b) 24480 c) 1400 d) 25200