A car dealership surveys 10,000 of its customers who have a GPS system in their cars to find out how often they have used it within the past month. The results are as follows:
Number of Times Used Customers with GPS
0 1382
1-5 2350
6-10 2010
11-15 1863
16-20 1925
21+ 470
a) What is the probability that a randomly chosen customer will have used the GPS system more than 20 times?
b) What is the probability that a randomly chosen customer will have used the GPS system no more than 10 times?
