Expert: Scott A Wilson - 3/20/2011

Question
A little help here? Anna is reading a 300-page book.  She can read a page in 2 minutes.  If she has finished reading 75% of the pages, how many minutes of reading does she have left?

Answer
If she reads a page in 2 minutes, then take the number of pages timjes 2 to get the number of minutes.  That is, since there are 300 pages, it would take her 600 minutes.  That is the same as 10 hours.  Now if she has already read 75%, then she only has 1 - 75% = 1 - 0.75 = 0.25 = 25% left to go.  Now since reading the entire book took 600 minutes, and she has 1/4 of the book left to to, we just need to do 600/4.  It is known that 6/4 = 1.5, so 600/4 is 150.