Mr. Walker plans to buy tickets for a play. He says:
Mr. Walker : There is a play at 7 pm on Friday. How about watching it together?
Mrs. Walker : Sure, that would be great.
Olivia : I’m busy but I can’t say no.
Oliver : It sorunds good but I have to attend an online course.
Owen : Yeah, why not?
According to the conversation above, how many tickets is Mr. Walker going to buy?