Standard normal distribution (statistic)?

IN A STANDARD NORMAL DISTRIBUTION FIND THE PROPORTION OF VALUES THAT LIE (I)ABOVE 2 (II)BETWEEN 0 AND -1/ SUPPOSE THAT VARIABLE X IS DISTRIBUTED WITH A MEAN OF 200 AND STANDARD DEVIATION OF 25 CALCULATE THE VALUE ABOVE WHICH 20% OF X VALUES LIE.IS THERE A FORMULA TO SOLVE THIS? IF YES WHICH FORMULA? THANKS