A speaker talked for 60 minutes to a full auditorium Twenty

A speaker talked for 60 minutes to a full auditorium.

Twenty percent of the attendees listened to the entire presentation while ten percent slept through the entire talk.

Divide the remaining attendees in half.

The first half is called Group A and the second half is called Group B.

Suppose p percent listen to the entire talk, ten percent slept, half of the remaining attendees heard one-third of the talk and the other half heard two-thirds of the talk. Explain

Solution

Suppose there are 100 people are in the auditorium and given that total talk was for 60 minutes.

1. Only 20 percent people listen for full 60 minutes. i.e. according to assumption only 20 people listen for full 60 minutes. In question it is also mention that P percent of people listen to entire talk therefore this P percent is 20 percent only.

2. 10 percent people were sleeping for entire 60 minutes therefore they did not listen any thing.

3. Now the remaining percent is 70 percent people.

4. Divide this 70 percent into equal halfs i.e. 35 percent each.

5. Now Group A and B both contain 35 percent of people.

6. Group A which contain 35 percent people listen one third of talk.(i.e. 20 minutes only)

7. Group B which also contain 35 percent people listen two third of talk.(i.e. 40 minutes only)