200 people were sampled and the following table shows the number of people with a certain average electric energy usage based upon the type of home an individual lives in:
Electric Usage (in kWh)
Type of Dwelling < 5,000 5,000 – 7,000 7,000 – 11,000 11,000 – 15,000 Total
Single Family 15 35 65 25 140
Multi-Family 25 15 15 5 60
Total 40 50 80 30 200
a) What is the probability of selecting someone who uses between 7,000 and 11,000 kWh?
b) What is the probability of randomly selecting someone who uses less than 5,000 kWh and who lives in a multi-family dwelling?
c) What is the probability of selecting someone who lives in a single family dwelling or uses between 5,000 and 7,000 kWh?