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Two teams of runners, the Eagles and the Swifts, took part in an event. The recorded times in seconds for 20 runners from the Eagles and 30 runners from the Swifts are denoted by 
and 
respectively. It is given that 
and that the mean of the times taken by all 50 runners is 8.54. It is also known that the standard deviation of the times taken by all 50 runners is 1.38 seconds. Find the value of 
, correct to 1 decimal place.
