If you read a 1 hour audio book and set the speed to 1.5 times faster than normal, how long will it take to listen to the entire book?

Question

If you read a 1 hour audio book and set the speed to 1.5 times faster than normal, how long will it take to listen to the entire book?

Answer 1

You would be led to believe it is a half hour.

But it's not.

Think of it like a ratio or proportion

 

Time x speed = # of books read

 

1 hour x (1 book/hour) = 1 book

 

       T  x       (1.5 books/hour) = 1 book

 

1 divided by 1.5 = 1 divided by 3/2 = 1 x 2/3 = 2/3

 

2/3 of an hour is 40 minutes