Lori in MS Posted April 27, 2010 Share Posted April 27, 2010 Please help me. I can't figure out how to do this problem. The ratio of the number of books that Lina had to the number of books that Sulung had was 1:2. After Lina bought 24 new books, the ratio became 2:1. How many books did Lina have at first? Thank you. Quote Link to comment Share on other sites More sharing options...
8filltheheart Posted April 27, 2010 Share Posted April 27, 2010 I don't know how to solve with bar diagrams, but here is an easy explanation: x= # of books Lina owns 2x= # for Sulung since Lina buys 24 books, that is x+24. That is the same as now 2 times what Sulung has so that is 2(2x). So.... x+24= 4x 24=3x x=8 Does that help? Quote Link to comment Share on other sites More sharing options...
fractalgal Posted April 27, 2010 Share Posted April 27, 2010 (edited) Please help me. I can't figure out how to do this problem. The ratio of the number of books that Lina had to the number of books that Sulung had was 1:2. After Lina bought 24 new books, the ratio became 2:1. How many books did Lina have at first? Thank you. Using the bar method: Here is the before case: Note: [ ] = 1 unit Lina [ ] Sulung [ ][ ] (Ratio is 1:2) After Lina bought 24 new books Lina [ ][ ][ ][ ] Sulung [ ][ ] (Ratio is now 2:1) So three units = 24 Then each unit = 8. So Lina originally had 8 books. Edited April 27, 2010 by fractalgal Quote Link to comment Share on other sites More sharing options...
forty-two Posted April 27, 2010 Share Posted April 27, 2010 The ratio of the number of books that Lina had to the number of books that Sulung had was 1:2. After Lina bought 24 new books, the ratio became 2:1. How many books did Lina have at first? L = Number of books Lina had to start with S = Number of books Sulung had to start with Initial (Lina's total books in blue): [----L----][-----------S---------] [----------][----------][----------] Final (Lina's total books in blue): [----L----][------------------+24-----------][-----------S---------] [----------][----------][----------][----------][----------][----------] To start with, Lina's initial number of books is declared to be equal to one unit of books. Since Sulung has twice as many books as Lina, Sulung therefore has two units of books. When Lina receives 24 more books, the ratio of books b/w Lina and Sulung becomes 2:1. Therefore, Lina's new total amount of books is twice as much as Sulung's amount of books. Since Sulung has two units of books, Lina now has 4 units of books. Those four units are equal to one unit plus 24 books, so 24 books equals three units, and one unit equals 8 books. So Lina had 8 books to start with. Does that make sense? Quote Link to comment Share on other sites More sharing options...
Lori in MS Posted April 28, 2010 Author Share Posted April 28, 2010 Yes thank you! Quote Link to comment Share on other sites More sharing options...
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