largest fraction of numbers less than 55 and more than 105 with the mean of 80 and the standard deviation of 5

Question

largest fraction of numbers less than 55 and more than 105 with the mean of 80 and the standard deviation of 5

Answer 1

Prob( x < 55) or (Prob( x > 105) =

Prob ( z < (55-80)/5) + (Prob ( z > (105-80)/5)

Prob( z < -5) + Prob ( z > 5)

Prob ( z < -5) + 1 - Prob ( z < 5) =

0 + 1 - 1 = 0