Question 924472
mean = 190 minutes , sd =  21 minutes, {{{z = blue(x - 190)/blue(21)}}}  
  Using the z-value to determine the Probability:
p( x < 217.51) = P(z < 27.51/21) = P( z < 1.31) 
Using a TI calculator 0r similarly a Casio fx-115 ES plus
P( z < 1.31) = normalcdf( -100, 1.31) = .9049  0r 90.49%