## Answer :

z-score for 20 = (20 - 25) / 5.8 = -0.8621

:

Note find probabilities from z-tables

:

Probability ( 20 < X < 30 ) = 0.8051 - 0.1949 = 0.6102

z-score for 20 = (20 - 25) / 5.8 = -0.8621

:

Note find probabilities from z-tables

:

Probability ( 20 < X < 30 ) = 0.8051 - 0.1949 = 0.6102