If each of the average ratings was the arithmetic mean of th

If each of the average ratings was the arithmetic mean of the ratings given by the 100 travel agents, approximately how much greater was the total of the ratings given to all three airlines for reliability than that for promptness?

Solution

total of the ratings given to all three airlines for reliability:
(7.8+7.5+4.9)*100 = 2020

total of the ratings given to all three airlines for promptness:
(6.5+6.9+4.1)*100 = 1750

2020-1750 = 270 which approximately equal to 250