Hi all , I using the http://road-to-psle.blogspot.com/search/label/Ratio as
a useful tools to teach the 2009 Syllabus .However i encountered
problem justifying certain numbers ..would appreciate if some kind
soul explain some part highlighted to me ?
Labels:
Mathematics,
Percentage
Emily bought a book. On the
first day, the number of pages of the book read was 25% of the
number of pages unread. On the second day, she read another 55
pages of the book. As a result, the number of pages she read was
80% of the number of pages unread. How many pages did the book
have?
Solution -
From the above image,
1st day ----- she read 1/5 of whole book
2nd day ----- she read 4/9 of whole book
Difference between 1st and 2nd days
(4/9 - 1/5) of whole book ----- 225
pages
11/45 of whole book ----- 225 pages
1/45 of whole book ----- 225/11 = 5 pages
Whole book ----- 5 pages x 45 = 225 pages
Answer: The book had
225 pages.
<<<how does the 225 pages comes
about initially ?>>>