In today's daily Target, Quant section.. question No.4 of "Sum of integral values of X", why the value 19 doesn't satisfy if we make the equation like x² - 18x -16 <= 2/5 then make it like 5x² - 90x -82 <= 0, till 18 it's fine but 19 doesn't satisfy the equation here, why is it the case here !? In the solution given there, it is solved in other way and it is satisfying, why not here by doing like this !?

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