The following is the frequency distribution for the speeds in miles per hour (mph) of a sample of 35 automobiles traveling on an interstate highway. The mean speed is: Speed (mph) Cumulative Frequency
50-54 2
55-59 6
60-64 11
65-69 21
70-74 30
75-79 35

One cell phone plan charges $20 per month plus $0.15 per minute used. a second cell phone plan charges $35 per month plus $0.10 per minute used. write and solve an equation to find the number of minutes you must talk to have the same cost for both calling plans.