The records of a computer retail store show that out of the 100 customers who purchased a desktop computer last month, 69 also purchased a service plan that extends the warranty for an extra year. Out of the 25 customers who purchased a notebook computer last month, 20 purchased the same service plan.
Last month, customers of the store who purchased computers were less likely to purchase the service plan, because either laptops or notebooks
did not purchase the service plan, whereas only laptops ot notebooks
of the customers who bought computers did not purchase the service plan.
Thank you for your help.