can you help me find the probabilities to these answers and the proportions

9. Speeding on the I-5 The distribution of passenger vehicle speeds traveling on the Interstate 5 Freeway (1-5) in California is nearly normal with a mean of 70.3 miles/hour and a standard deviation of 5.2 miles/hour. (a) What proportion of passenger vehicles travel slower than 79 miles/hour? (b) What proportion of passenger vehicles travel between 58 and 75 miles/hour? (c) How fast do the fastest 15% of passenger vehicles travel? miles/hour (d) Find a value k so that 60% of passanger vehicles travel at speeds within k miles/hour of 70.3mph. k = (e) The speed limit on this stretch of the I-5 is 70 miles/hour. Approximate what percentage of the passenger vehicles travel above the speed limit on this stretch of the I-5