A Cell Phone Salesperson Has Kept Records on the Customers

Short Answer

A cell phone salesperson has kept records on the customers who visited his store. Forty percent of the customers who visited the store were female. Furthermore, the data show that 35% of the females who visited his store purchased a cell phone, while 20% of the males who visited his store purchased a cell phone. Let A₁ represent the event that a customer is a female, A₂ represent the event that a customer is a male, and B represent the event that a customer will purchase a phone.
What is the probability that a female customer will purchase a cell phone?