The possible rational roots of x^3 + 5 x^2 + 2 x - 8 are x = ± 1, x = ± 2, x = ± 4, x = ± 8. Of these, x = 1, x = -2 and x = -4 are roots. This gives x - 1, x + 2 and x + 4 as all factors:
<span>Since one standard deviation is 20 luggages, 3 standard deviations above the mean is 3*20=60 luggages above the mean of 380 luggages, so 60+380 gives the answer C, 440.</span>
