For a daily airline flight between two cities, the number of pieces of checked luggage has a mean of 380 and a standard deviation of 20. on what percent of the flights would you expect from 340 to 420 pieces of checked luggage?

340 is (340-380)/20=-2, or 2 standard deviations below the mean.
420 is (420-380)/20=2, or 2 standard deviations below the mean.

 95% of values lie within 2 standard deviations of the mean, so the answer is 95%.

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right