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Question 5 (a) A flu epidemic is spreading in a village and the number of people n who are infected on any particular day t after the outbreak started is given by n(t) = 90t2 - 2+3 (i) Find the number of people infected on day 3 . ( 2 marks ) (ii) What is the maximum number of people infected? On which day does this occur? ( 6 marks ) (iii) On which day ( t > 0 ) are there no infections? ( 2 marks ) (b ) The base of a rectangular block has a length which is twice the width, x and height h . The block has a total surface area of 300 cm 2. 2x X (i) Express h in terms of x . ( 3 marks ) (ii) Hence, find the volume of block, V (x) . ( 2 marks ) (iii) Find the dimensions of the block when the volume is maximum. ( 5 marks )