,The average age for a person getting married for the first time is 26 years (U.S. News and World Report, June 6, 1994). Assume the ages for first marriages have a normal distribution with a standard deviation of four years.,a) What is the probability that a person getting married for the first time is younger than 23 years of age?,b) What is the probability that a person getting married for the first time is in his or her twenties?,c) 90% of people getting married for the first time get married before what age?,,PLEASE SHOW THE WORKING OUT, THANK YOU VERY MUCH